A thread protector for the receiver threads on your Silverback Airsoft SRS when in Gspec format. This one is threaded 16mm+, just in case you want to heretically fit the suppressor from the TM Mk23.
NOTE: Will not work with the Silverback gspec outer barrel. Will only work with the short outer barrel base found here....
https://www.shapeways.com/product/NNJQQ8Z64/srs-outer-barrel-base?optionId=96105294