The UKPK has become one of my favorite EDC knife. I have a Caly3 in G10 and one in Carbon Fiber but I prefer the Orange UKPK. The slip joint back spring is very srong and should not close under normal use. It also has a half stop which is found on some slip joints and was done on a lot of older slip joints. BTW, years ago I carried traditional slip joints but in the seventies started carrying Buck and Gerber lock backs. I actually prefer a single blade knife as I find multi blade knives to be a little uncomfortable with use as the back of the closed blades dig into my hand. The ease with which the UKPK can be opened and closed is addictive and has made me reevaluate whether I need a lock on a folder. Along with the excellent steel S30V and outstanding edge geometry makes this one sharp cutter! And the fine ergonomics of the knife as with most Spydercos make it a fine EDC. Once you see what a Spyderco knife is about it spoils you for other knives. BTW, I have more knives by many companies so I have tried most of them. Sal and his gang has come up with a real winner.
RKH
RKH