Galaxy Watch 4 Band Size: They All Take 20mm Bands
2 Packs No Gap Metal Bands Compatible with Samsung Galaxy Watch 4 Band 40mm 44mm/ Galaxy
The best Samsung Galaxy Watch 4 bands - Android Authority
Best Straps/Bands for the Samsung Galaxy Watch4/Watch4 Classic! Compatible with Watch 5/5 Pro too! - YouTube
OTOPO Compatible Samsung Galaxy Watch 5/4 Band 40mm 44mm,Galaxy Watch 5 Pro Band Leather, Galaxy Watch 4 Classic Bands 46mm 42mm, Active 2 Bands,2Pack 20mm Leather Strap Replacement Band for Men Women :