Based on this product's specifications, here are some alternatives and similar models
Label roll NIIMBOT R 40×20 mm white — 320 pcs for Niimbot B21, B21S, B3, B1S
Summary description:
Thermal label roll NIIMBOT R, 320 white labels sized 40×20 mm compatible with Niimbot B21, B21S, B3 and B1S series printers. Self-adhesive, die-cut rectangular labels on a roll for printing barcodes, price tags, shipping marks and product identification. Designed for direct thermal printing; suitable for retail, warehouse, logistics and office labeling tasks.