The movement is a 20 jewel version of the Seagull ST6 (TY6DSK(6103K))- the lightness of the watch is partially explained by the tiny movement. It is a skeletonized 19.8mmx4mm ladies' version of the movement and has a fairly large plastic movement holder. I picked mine up last summer when it was on sale for $99, and added another 15% coupon to get the watch for $85 (~69GBP). My wife didn't like the look of the original strap, so I picked up an 18mm padded leather strap... as most other straps will be tapered, I think that they make an already small watch look even smaller, so I prefer it on the original nylon strap, which is quite comfortable.