As wetsuit manufacturers continued to develop suit designs, they found ways that the materials could be further optimized and customized. The O'Neill Animal Skin created in 1974 by then Director of Marketing, E.J. Armstrong, was one of the first designs combining a turtle-neck based on the popular Sealsuit with a flexible lightweight YKK horizontal zipper across the back shoulders similar in concept to the inflatable watertight Supersuit (developed by Jack O'Neill in the late 1960s). The Animal Skin eventually evolved molded rubber patterns bonded onto the exterior of the neoprene sheeting ( a technique E.J. Armstrong perfected for application of the moulded raised rubber Supersuit logo to replace the standard flat decals ). This has been carried on as stylized reinforcing pads of rubber on the knees and elbows to protect the suit from wear, and allows logos to be directly bonded onto raw sheet rubber. Additionally, the Animal Skin's looser fit allowed for the use of a supplemental vest in extreme conditions.