Alligator Cable Housing Ferrule - Bag of Twenty4mm and 5mm metal Ferrule's come in bags of 20 with a chrome finish.
Great value for these little guys, I have a nice set of spares now for all my bikes.
Good quality metal, every bit as good as the expensive ones I bought last time.
Combine these with a large roll of housing and cables, and you'll have everything you'll ever need to replace cables for the next 10 years for you and your friends! They've been working great for me and I just use a pair of pliers to crimp them down.