Bottom bracket, ideal for refurbishing bikes that have older non-cartridge bottom brackets. Can be installed to immediately remedy creaks and clunks from the cranks.
Installation is a snip (once the old bottom bracket has been removed). For this you will need Park Tool 'BBT-22' (£13.95) and a crank tool such as Park Tool 'CWP6C' (£13.95). The cranks will need a further tighten after some riding, after that the bottom bracket should be maintenance free.
It helps to get the right size bottom bracket. 68mm shell width with 113mm axle length is the most popular size, however you will have to measure the existing bottom bracket to avoid time-consuming mistakes.
If living locally you can book the bike into the workshop to get this installed - contact us for a quote. If doing-it-yourself, see the Park Tools website for more instructions:

http://www.parktool.com/repair/readhowto.asp?id=103