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Exhibit 4.2

Summary of Lease
Agreement, dated November 20, 2008, between
Silicom and Naji Yechezkel Yokenam Industrial Center Ltd. (the Lessor)

Note: this Summary does not
contain a full or direct translation of the terms of the original Hebrew-language
agreements, and is intended solely as a general presentation of these documents.

Leased Premises

900 square meters (gross) on the
first floor of a building project located in Yokneam Ilit.

Term of Lease

|1) | The
Term of Lease will be 24 months, ending in December 31, 2010.
|-- | -----------------------------------------------------------------

|2) | We
will have the option of extending the Term of Lease for three additional           years.
In the event we do not wish to extend the Lease, we must notify Lessor 60           days
before the end of the original Term.
|-- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Purpose of Lease

Premises will be used as offices and
a high-tech plant only. Any other use will be contingent upon Lessors prior written
consent.

Rental Payments

|1) | During
the Term of the Lease (and the option, if applicable): NIS 40 per square           meter,
which will be linked to the consumer price index on the date of each           payment;
the minimum index will not be less than 107.1.
|-- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|2) | Rental
payments will be paid every three months, on the 3rd day of           the
month in which the payment is due.
|-- | -------------------------------------------------------------------------------------------------------------------

|3) | Upon
each date of payment, we will pay VAT according to law.
|-- | ------------------------------------------------------------

Use and Preservation of
Premises

|1) | We
will be liable for any injury, damage or loss caused by us to the Leased
          Premises, the Lessor, or any other person or corporation, resulting from the
          holding and/or using the Leased Premises or any other action or omission by the
          us or someone on our behalf.
|-- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|2) | We
will be responsible for the current maintenance of the Leased Premises and           will
make the repairs for the damages for which we are responsible under the           Lease.
The Lessor will make all repairs for damage for which we are not liable,
          including reasonable wear and tear or structural damage.
|-- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|3) | We
will not make any changes in the premises without Lessors prior written
          permission.
|-- | -------------------------------------------------------------------------------------------------



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Taxes, Permission,
Licenses and Management Fees

|1) | We will pay all taxes and utility bills, apart from governmental property tax
          and any taxes applicable to property owners.
|-- | ------------------------------------------------------------------------------------------------------------------------------------

|2) | We will be responsible for procuring any necessary licenses from the
          authorities.
|-- | -------------------------------------------------------------------------------------------

General

|1) | Lessor may assign or transfer its rights pursuant to the Lease, provided that
          our rights are not reduced or infringed.
|-- | --------------------------------------------------------------------------------------------------------------------------------

|2) | We undertake not to assign its rights pursuant to the Lease or to sublet the
          Leased Premises without the prior written permission of Lessor. Lessor will
          refuse only on reasonable grounds.
|-- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Insurance

We will procure the following
insurance policies: Property insurance; third-party liability insurance; employer
liability insurance.

Surrender of Premises

Belated surrender of premises will
obligate us to pay two times the usual rental payments for any duration exceeding the end
of the period of lease, according to the dollar rate at the time of the Breach, which will
be no less than NIS 4 for each $1.

Termination of the
Agreement

The Agreement can be terminated prior
to the end of the Term upon the occurrence of any of the following events:

|1) | We
breach any of our obligations under this Agreement and do not amend such
               breach within 14 days as of the date on which we were were provided with a
               written notice to amend such a breach; then, the Lessor will have a right
to                terminate the agreement.
|-- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|2) | In
the event that a receivership order was issued against us, which was not
               canceled within 30 days.
|-- | -------------------------------------------------------------------------------------------------------------------

|3) | In
the event that a liquidation order was issued against us, which was not
               canceled within 30 days.
|-- | ------------------------------------------------------------------------------------------------------------------

Guarantees

|1) | We will provide an autonomous bank guarantee at an amount equal to three months
          of rental payments, including VAT.
|-- | ----------------------------------------------------------------------------------------------------------------------------

|2) | In the event that we breach this Lease, the Lessor would be able to exercise the
          bank guarantee.
|-- | ----------------------------------------------------------------------------------------------------------

|3) | The Guarantee will be returned 60 days after the end of the Term or the term of
          the option, as applicable.
|-- | --------------------------------------------------------------------------------------------------------------------

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