Katana Owners Club U.K.

I’ve always done it by hand?
Fit one open end in the groove then using an electrical screwdriver hold that in place and then use your thumb to push the remaining end in. Finish off using the screwdriver to seat the whole circlip in the groove. Job done. If you fit the inner circlip first on the bench first it makes the job easier. Fill the open crankcase mouths with rags just in case

Mmmmm neat bit of kit, I always struggle with sausages for fingers, mind you it has been years since any Pistons have be bothered by them!

Certainly looks like a nice tool, that should ease any worries during gudgeon pin circlip installation.