We were able to conclude 2020 with $365 million of revenue and $32 million of adjusted EBITDA.
We estimate that this, combined with our other e-Series technology products, will save operators approximately $5 million per well and five days of rig time.
First, it allowed us to offer our customers the latest subsea controls technology without having to make the significant research and development investment of $8 million to $10 million per year over the next three years, as well as eliminated the associated operating costs of maintaining that product line.
This strategy led us to the difficult decision to transition and consolidate our subsea tree manufacturing from Aberdeen to Houston as we saw the subsea tree market decline from close to 300 subsea trees to a little over 100 tree awards in 2020.
In total, the productivity initiatives executed in 2020 reduced our costs by approximately $20 million on an annualized basis and helps us to continue on maintaining profitability and a strong balance sheet.
A large part of these commitments, in some cases, as high as 70% reduction in carbon emissions, will come from the vendors who supply these companies.
For example, the combination of our e-Series technologies can help reduce roughly 40 tons of steel from traditional operations.
The elimination of this component alone reduces carbon emissions by approximately 70 tons as the process needed to produce the steel is no longer required.
Revenue for the fourth quarter fell slightly from the prior quarter to $87 million.
This decline was mainly due to lower manufacturing production hours related to increasing levels of quarantines from rising COVID-19 cases, seen mainly in the U.S. Adjusted EBITDA for the fourth quarter was $9 million, a decrease of $1 million from the prior quarter.
For the full year 2020, our revenues were $365 million, a decrease of $50 million versus 2019.
Adjusted EBITDA for the full year 2020 was $32 million, a decrease of $22 million from the previous year.
We met our $20 million cost reduction target in 2020.
But given the environment, it held up falling by only 3%.
We saw EBITDA margins improve 3% from the first half to the second half 2020 after normalizing for mix and the impact of disruptions related to COVID-19.
For the fourth quarter of 2020, SG&A was $26 million, an increase of $5 million compared to the third quarter.
For the full year 2020, SG&A expenses decreased by $8 million to $90 million after excluding these short-term legal expenses.
On the engineering R&D side, we saw a modest increase in 2020 to $19 million as we work to bring the VXTe to market.
After approximately $388 million in bookings during 2019, the uncertainty surrounding the pandemic and its impact on commodity prices led to customers holding off or delaying decisions to book orders for their upcoming projects.
We now see one or two orders being the difference between a $40 million or a $60 million bookings quarter.
We are taking actions related to our productivity initiatives driven by our LEAN management philosophy and are targeting a $10 million cost improvement on an annualized basis.
The timing of these productivity actions will take place over the course of the year and is expected to deliver roughly $5 million of realized benefit in 2021.
In the fourth quarter of 2020, our capex totaled just under $2 million.
And for the full year, it was around $12 million.
We are, however, anticipating an increase in capex to range in between $15 million to $17 million in 2021.
At year-end, we had cash on hand of $346 million and a further $40 million of availability in our ABL facility.
This results in approximately $386 million of available liquidity.
Free cash flow for the fourth quarter was a negative $18 million.
For the full year, it was negative $33 million.
In the current environment and given the initiatives I just mentioned, we expect to be able to generate 5% free cash flow yield.
Based on the current view and the conversations with customers, we expect 2021 bookings to be around $200 million for the year.
We are forecasting 40% decremental margins for any given decline in revenue as we hold costs critical to address a recovery.
As I mentioned earlier, we are forecasting a free cash flow yield around 5% in 2021.

Summary:
We now see one or two orders being the difference between a $40 million or a $60 million bookings quarter.