Types: Rim, Oval, Euro, Scandinavian and screw in.
Finishes include: Brass, satin, chrome.
Common sizes: 30/30, 35/35, 40/40 etc.
Commonly found: Multi point locks on UVPC doors, dead locks, sash locks.
Key features: The keys can ether be flat with dimples on both sides or have a serese of cuts along the top (5 or 6 depending on the cylinder)
The brands that may be on your door include: Yale, Asec, Brisant, Ultion, Assa, CarlF, UAP, TSS, ERA, Anker, Legg, EVVA
The cylinder in the photo was fitted in Reading, Berkshire.