Patent ID: 6858567

Claim:
A watch having a movable portion lubricated with a lubricating oil composition comprising a base oil comprising a polyol ester (A), a viscosity index improver (B) in an amount of 0.1 to 20% by weight and an anti-wear agent (C) in an amount of 0.1 to 8% by weight, said oil composition having a kinematic viscosity of not more than 1500 cSt and not less than 13 cSt at −30 to 80° C., a weight change of not more than 1.62% by weight after allowed to stand for 1000 hours at 90° C. and a total acid number of not more than 0.2 mgKOH/g, wherein: the polyol ester (A) has a kinematic viscosity at −30° C. of not more than 1500 cSt, and the anti-wear agent (C) is a neutral phosphoric ester and/or a neutral phosphorous ester.