Suppose you can weigh them if you have accurate scales. Stock is 6.5g. If you order a set you just ask for whatever weight you want, i.e 5.5g, 6g, 6.5g, etc. The size you need is 16x13 then the weight you need. So for Stock you want 16x13, 6.5g rollers.
None of mine have ever had a weight stamped on them. They have a brass insert covered by plastic/nylon stuff, the brass is thicker so heavier in the heavier weights. If you look at them on the ends you can tell if one is heavier or lighter by comparing the thickness of this brass.
