RobotDigg T5 Timing Pulley 10 Teeth 5mm Bore for 15mm Wide T5 Timing Belt Aluminum Alloy T5 Synchronous Pulley Pack of 2

I didn't realize there was so much variety in these motor mount pulleys, and confusing / non-consistent naming and labeling of the parts. T5 Timing Pulley 10 Teeth 5mm Bore for 15mm Wide T5 Timing Belt Aluminum Alloy T5 Synchronous Pulley Pack of 2 T5 = teeth spacing on the belt, T also seems to indicate the shape of the tooth on the belt. 10 Teeth = number of teeth on the pulley. 5mm bore = diameter of post size fitting into the center of the pulley. 15mm wide = width of belt to use on the pulley. The pulleys have "timing" indicated by the spacing of the teeth on the belt it supports. The teeth are measured between center of a peak, to the center of the next adjacent tooth peak on the belt it supports. The included image shows a close up of the different shapes of the belt teeth you may run across. The T5 in the part name indicates it supports a 5mm interval belt, the width of the belt being 15mm. (wide belt) I've come across belts labeled AT5 and T5 I was actually looking for a T3 supporting pulley, so I got this in error. The build quality looks good, and the machining on it is clean, no burrs, no rough edges, clean teeth. After doing some research, I've found that there are both metric and imperial standards on both the belts and the pulley spacing. Belts labeled XL (1/5", 5.08mm), L (3/8", 9.525mm), H(1/2", 12.7mm), XH(7/8", 22.225mm) all appear to be imperial. The shapes of the teeth on the belts I found for metric are labeled as follows: T, AT - trapezoidal tooth? (some mfg seem to sell rounded teeth with this naming convention) HTD - rounded tooth GT, MX, YU - rounded? Seems to be partially standard, partially mfg specific naming. (Ex, Ive seen 2GT and GT2 both to indicate 2mm spacing.) I haven't sorted through the differences completely myself, but hopefully this gives other enough google terms to find specifics to what your application may need.