Adding a PoE Injector: 30W? 60W? 95W? Which to Choose?

This video mainly shows us the difference among three different POE injectors. The market includes 30W, 60W, and 95W injectors. When we plan to apply an injector to the system, how should we choose? We need to understand the 30W injector will not just output 30W high power to the device, it has to match with the receiving device due to the IEEE 802.3 protocol. Once they match, the power can go through and power the device. In conclusion, we should make sure how much power we need first, then choose the right injector.