This is a brass taffrail log manufactured by TSK in Yokohama Japan.  The model is T.S. Ship-Log, Type E and was used on ships to measure distance through water. The number of times the spinner turned in the water would register on the meter as miles traveled. I have not been able to test it so I don't know it's working condition. The log measures 10 1/2" deep, and is 6" wide with a 4" dial. It weighs 13 lbs. It comes with one brass spinner that is 14" long. The pictures show two spinners but it only comes with one.The wood case is in good condition with some veneer chipping on the lid as shown in the pictures.