A system for providing energy to a tissue, comprising a plurality of microwave energy delivery devices and a spacer configured to position the microwave energy delivery devices, the spacer comprising: a housing, including: a housing body forming a housing body cavity and a plurality of housing device apertures (302a, 302c); a compression body forming a plurality of compression body apertures (302a', 302c') each corresponding to one of the plurality of the housing device apertures (302a, 302c), the compression body being configured to slideably engage the housing body cavity, wherein at least a portion of the compression body is positioned in the housing body cavity; and a first compression mechanism including at least one spring (320a, 320c) positioned between the housing body and the compression body, the first compression mechanism being configured to provide a biasing force between the compression body and the housing body, wherein: - in a first position, with the at least one spring (320a, 320c) substantially uncompressed, the plurality of housing device apertures (302a, 302c) are misaligned with the plurality of compression body apertures (302a', 302c'); - in a second position, with the at least one spring substantially compressed, the plurality of housing device apertures (302a, 302c) are aligned with the plurality of compression body apertures (302a', 302c'), thus forming a plurality of aligned aperture pairs configured to receive a microwave energy delivery device therethrough, - in a third position, the housing body and the compression body apply a first biasing force, generated from the first compression mechanism, to hold the microwave energy delivery device through one of the plurality of aligned aperture pairs, so that, when the compression body is released from the second position with one or more microwave energy delivery devices positioned in the respective aperture pair, the compression body is configured to be driven by the at least one spring (320a, 320c) toward the first position so as to contact the microwave energy delivery devices in the housing device apertures (302a, 302c) in the third position, wherein the compression body comprises an outer portion extending beyond the housing body in the first position. a housing, including: a housing body forming a housing body cavity and a plurality of housing device apertures (302a, 302c); a compression body forming a plurality of compression body apertures (302a', 302c') each corresponding to one of the plurality of the housing device apertures (302a, 302c), the compression body being configured to slideably engage the housing body cavity, wherein at least a portion of the compression body is positioned in the housing body cavity; and a housing body forming a housing body cavity and a plurality of housing device apertures (302a, 302c); a compression body forming a plurality of compression body apertures (302a', 302c') each corresponding to one of the plurality of the housing device apertures (302a, 302c), the compression body being configured to slideably engage the housing body cavity, wherein at least a portion of the compression body is positioned in the housing body cavity; and a first compression mechanism including at least one spring (320a, 320c) positioned between the housing body and the compression body, the first compression mechanism being configured to provide a biasing force between the compression body and the housing body, wherein: - in a first position, with the at least one spring (320a, 320c) substantially uncompressed, the plurality of housing device apertures (302a, 302c) are misaligned with the plurality of compression body apertures (302a', 302c'); - in a second position, with the at least one spring substantially compressed, the plurality of housing device apertures (302a, 302c) are aligned with the plurality of compression body apertures (302a', 302c'), thus forming a plurality of aligned aperture pairs configured to receive a microwave energy delivery device therethrough, - in a third position, the housing body and the compression body apply a first biasing force, generated from the first compression mechanism, to hold the microwave energy delivery device through one of the plurality of aligned aperture pairs, - in a first position, with the at least one spring (320a, 320c) substantially uncompressed, the plurality of housing device apertures (302a, 302c) are misaligned with the plurality of compression body apertures (302a', 302c'); - in a second position, with the at least one spring substantially compressed, the plurality of housing device apertures (302a, 302c) are aligned with the plurality of compression body apertures (302a', 302c'), thus forming a plurality of aligned aperture pairs configured to receive a microwave energy delivery device therethrough, - in a third position, the housing body and the compression body apply a first biasing force, generated from the first compression mechanism, to hold the microwave energy delivery device through one of the plurality of aligned aperture pairs, so that, when the compression body is released from the second position with one or more microwave energy delivery devices positioned in the respective aperture pair, the compression body is configured to be driven by the at least one spring (320a, 320c) toward the first position so as to contact the microwave energy delivery devices in the housing device apertures (302a, 302c) in the third position, wherein the compression body comprises an outer portion extending beyond the housing body in the first position.