a comb in which the pointed parts are thin and very close together 细齿梳子
Idioms
go over/through something with a fine-tooth/fine-toothed comb
to examine or search something very carefully 十分认真地检查；非常仔细地搜查 The police have gone over the house with a fine-tooth comb. 警察用细齿梳子扫了整个房子。