This is a TOSHIBA TEC label, part number LTX010010R1ST-YLW. It is a 1-inch circular, non-perforated, yellow label designed for thermal transfer printing. Each roll contains 500 labels, and they are sold 4 rolls per case.
LTX010010R1ST-YLW - Toshiba TEC, CONSUMABLES, LABEL, TT, NON-PERF, 1" CIRCLE, YELLOW, 500/ROLL, 4/CASE, 3" ID - 4" OD, W