3/8" Binding Combs

No, color is purely cosmetic at this size; all colors use the same PVC construction, hole pattern, and sheet capacity. Choose based on what matches your cover, brand color, or department coding rather than worrying about any functional tradeoff between, say, black and navy. The one practical consideration is availability, since some colors move faster than others and may need reordering more often for high-volume use. For browsing the full range of colors currently offered at this size, comb binding supplies by color makes that easy.

That depends on how close your typical stack runs to the top of the 5/16" range rather than assuming the next size is always the right move. If your documents are consistently landing near the upper end of what 5/16" comfortably holds, stepping up to 3/8" gives you room without over-sizing. If your page counts vary a lot from project to project, it may be worth keeping both sizes on hand rather than standardizing on just one step up. For comparing diameters side by side, comb binding supplies by size makes that easier.

No, the hole pattern itself, typically 19-hole for standard letter documents, stays the same across most comb diameters; what changes is the comb's outer diameter, not the punch spacing. The pattern needs to match your binding machine and document width, but you don't need a separate punch setup just because you're moving between comb sizes like 5/16" and 3/8".

Yes, as long as the added pages still fit within the comb's rated capacity once reopened. Reopen the comb with a comb opener or compatible machine, insert the additional punched pages in order, and close it again the same way it was originally bound. If the added pages push the stack past what 3/8" comfortably holds, that's the point to move up a size rather than forcing an overfilled comb closed. The broader binding combs range covers every size and color together if your needs change down the line.