Ask the internet: Sprung pins

[numberland]

I need 4 sprung pins like you get on walking sticks (the type you get that you can push in but springs back out when not under pressure like shown in http://www.chemist.net/sysimages/origimages/zt-0610r_sp1673.jpg). My google foo is failing me in terms of finding a supplier for these - particularly as I have a fixed size hole to get it into. Oh, internets where might I get shall items from? I have tried Mackeys, B&Q, Homebase and Ebay as best I can. I may be lacking a proper search term.