I had a custom Imperial wetsuit around 1973, when dry suits were pretty scarce and real expensive. I used my Imperial until around 1985. The left arm appeared to be a different lot of material than the rest of the suit. The exterior fabric delaminated entirely, but just on the left arm. I used this suit with great satisfaction in the 40-50 deg water off the coast of CA and in the 35 deg water of Lake Superior. My suit was a custom design by the Olympic Scuba School in Walnut Creek, CA. Dave Olson, the owner, had developed the extra-warm suit for northern California diving. It kind of amazes me now to see dry suits being used in 68 degree water.