In this prosthesis for pneumatic knee joints, iglide® J piston rings replaced previously used PTFE guide bands. The piston rings are light, low friction guides that absorb radial forces and stabilize the swing phase of the joint. The piston rings can also be clipped quickly and easily, which reduces installation time and assembly costs. Wear and tear tests on iglide® J piston rings showed virtually no evidence of deterioration. The functionality, quality and durability of the knee joint were enhanced with iglide®.