He is on another forum I read and gives good advice. I've had abrasives from him privately for a B&D power file and my belt sander/grinder and always had good results.
If you want to know the size of belts[or bandsaw blades] for that matter, if both wheels are the same size then measure the diameter & multiply by pi then measure the center to centre distance apart of the wheels & multiply by two,add to the other measurement & you have got the belt/blade length, all you need to do then is select the grade.