Snail cams are the lightest and neatest way of tensioning your chain and it's the most common system on 20" wheeled bikes. To use snail cams you need to have a bolt head situated on the inside of your frame's dropout face a few millimetres in front of the dropout slot. Most frames have these already included from new, but if you don't have any then it's very likely you will have some threaded holes into which you can fit some Try-All Snail Cam Bolts.
There are two main types of snail cam, ones with teeth around the outside edge and those which have a smooth outer edge. The toothed snail cams offer more definitive 'clicks' when you add tension to the chain and tend to stay in place more effectively, whereas the smooth snail cams offer a better resolution of adjustment.
Tensioning your chain with snail cams is very easy, we have a video guide here.
Please note that some of the Echo snail cams have a 12mm instead of 10mm hole. These are ideally designed to fit specific models of Echo hub, but will work on hubs with a 10mm axle too, just a little less efficiently.
TartyBikes Ltd, Units 3-4, Club Street, Bamber Bridge, Preston, PR5 6FN