There are 11 products.
Flange Nut - Allows mounting of stud on hollow fore-ends.
Flange Nut - for M14 or M1A Has radiused flange for mounting to wood or polymer fore-ends under gas tubes.
Universal Adapter - Requires two inches of unclutered barrel for mounting. Fit barrels from .550 diameter to .812.
Stud - For European Size Rails. (3/8" across rail slot)
Harris Bipod Adapter Houtschroef MK250201.