Many 50mm Suzuki shocks from 2009-15 have an "interesting" piston ring design that seals OK but has massive drag (really bad-strongly recommend a Gold Valve).
This seal gets stuck in the circlip groove during disassembly, often destroying it
This Piston Ring Tool fits into, and fills, the circlip groove allowing the seal to easily slide past
It doesn't remove the massive friction (uhh, have I mentioned Gold Valves?) but it does allow removal of the shaft assembly!