RSA MP5K

If you are SBRing an SP5K, this is a great adapter to allow you to use Sig folding telescopic stock or any other stock that utilizes 1913 rail. This adapter allows you to adjust the height of your cheek weld to permit ideal use of iron sights or an optic. Just put the stock higher or lower based on what you are using. Excellent adapter. Fit is snug but why would you want it loose? I'm no fan of wobble and so I find this to be of excellent quality. Honestly, great balance of aesthetic and ergonomics in my opinion.