Will you engrave on my Brand Name tumbler?

We will from time to time, engrave on customer-supplied items if there is large enough quantity for us to be able to do testing to ensure quality. The powder coating thickness and hardness is a bit different from every tumbler manufacturer. Even various colors within the exact same make and style of tumblers can vary in the amount of power needed. Too little power and the laser doesn’t get through the powder coat. Too much power and the stainless steel underneath can get damaged. 
Our aim is that our customers get an engraving they are thrilled with, and testing on each specific material and color allows us to dial in our settings properly. 
If you have backups that we can test on, we would be happy to engrave on your brand name tumblers for you. 
We do keep a large selection of Polar Camel tumblers in stock, in all the colors, and in 4 different sizes. We know the settings required for those, so if you would be open to those we can turn them very quickly for you.