On the buckets we have tested, the product fits without a problem. For the 3" and 4" Edge Tamers, the opening on the back of the Edge Tamer is 1″, which should be plenty of space (for the 6", it is closer to 1 7/8"). You may note in the pictures how much space is available. One exception are buckets with removable, bolted-on edges. The combined thickness of those edges can be more than 1", and therefore incompatible with the Edge Tamer. If you are especially concerned about a fit, here is a 3"/4" template and a