On the balances number written UB. 288

Thanks for posting. This is possibly an S380-29 Channel Balance, with a stamp option of 2830. However, please check the depth of the bottom nylon shoe, or the measurement from 'heel-to-toe'. See the diagram below for reference. The Series 380 has a shoe that is 1" deep. I suspect your shoe might be less than 1" deep. Please let us know if that is the case before proceeding.

Comparison of the S378, S380 and S385 balance shoes.