This looks to be a ko-kinko school tsuba. It is made of Yamagane and has a very pleasing wave design carved into the surface. Judging by the size of the nakago ana, it was on a rather large sword at one time. It measures 2.5 inches or 6.4 cm by 2.48 inches or 6.3 cm. The overall condition is very good. It could be quite old.