Full Speed Ahead Seatpost Top Clamp AssemblyMTC for RK-150 SP-RK-150 0SB. The FSA Seatpost Top Clamp Assembly is a replacement component designed to secure saddle rails to compatible FSA seatposts. Built for durability and precise fit it ensures reliable saddle positioning and easy installation. This assembly is ideal for riders maintaining or upgrading their FSA seatpost hardware.