ONLY FOR FULL ROTATION BASES DO NOT USE ON NON-ROTATING OR LIMITED ROTATION MOUNTS. - Add function to push button swivel bases with the ingenious Multi-Adaptor. Use supplied allen wrench to depress plunger and slide into base. Standard stud is ready to accept all swivel types and/or mounting of bipods and accessories that require standard studs. Fits all standard push button swivel bases. Set includes two Multi-Adaptors and two stainless steel bases.