Codenamed CT-5, this chain tool is really quite small (weighing 77g) so shouldn't cause problems fitting it in any size of saddle bag. You can buy replacement pins (CTP) when the pin provided gets burred or bent. The question is, how well does it hold up at removing and re-linking chains?
Purchased in August 2011 So far the chain tool has only been used twice: to remove an old Shimano 105 chain, and to remove a spare link from a new SRAM chain. The new chain features a powerlink, so doesn't use a chain tool for fitting. On both occasions, the tool took a bit of effort to get the first quarter turn, but the alignment was true and the chain tool's pin didn't slip around.