Conn Res-o-Pads
Between 1920 and 1947, all professional-grade saxophones manufactured by C.G. Conn had rolled toneholes. In the early 1930s, Conn developed a unique type of saxophone pad called "Conn Res-o-Pads", which were specifically designed for use on saxophones with rolled toneholes. Conn Res-O-Pads have an internal metal reinforcing ring which is hidden under the leather covering around the circumference of the pad. Their most notable feature is that the diameter of the pad extends over the rim of the key-cup, thereby giving a slightly wider surface area for the rolled tone-hole to seal onto. Rim impressions from Res-o-Pads are minimal and unlike standard pads they cannot be "floated" in. Though designed to fix into key-cups purely via friction, most saxophone repairers glue them in place using shellac or hot melt adhesive. Res-o-Pads can be challenging to size correctly because (unlike standard saxophone pads which come in 0.5 mm size steps) they are only available in 1/32nds of an inch sizes which may not always correspond closely to key-cup diameters. Newly produced Conn Res-o-Pads are still available from specialist suppliers and are favored by some saxophone collectors because they give a fully authentic look and feel to vintage saxophones with rolled toneholes e.g. those made by Conn, Kohlert and Keilwerth. However, it is possible to fit standard pads to any saxophone with rolled toneholes (and many people do) without any noticeable disadvantage regarding the quality of sound produced.
Read more about this topic: C.G. Conn