Only authentic sentol bottle openers have patent number 4414866 stamped underneath. The patent has expired which is why you find many sentol imitations on the market. Our white bottlepal is genuine sentol. Many of these imitations are low quality so be careful. We attended trade shows in asia and tested many imitations and finally found one that met our high quality standards: Our red bottlepal opener. Our red opener is a sentol imitation but its quality is higher than other imitations and we are able to pass our cost savings on to you!