Replaces the standard HK VP9 P30 magazine floor plate with a rail adapter so you can attach the MantisX to your firearm if it doesn't have an existing rail, or if you want to work with holster draws . For the VP/P series (Part number: MT-2063): compatible with: VP9, VP40, VP9SK, P30, P30L, P30S, P30SK For the 10 round only (Part number MT-2018): compatible with: VP9 10rd, P30 10rd, P30L 10rd, P30S 10rd