An adjustable drum head retaining and tuning system and associated method is disclosed. Also, a multilayered structure including a plurality of adjacent layers, at least one of which has the above composition. The user may be presented with a visual medium. The computer network for electronically trading derivative comprises: network managing station; one or more market maker stations; one or more subscriber stations; one or more Exchanges. This appraisal process may also include a multiplier derived from comparisons of registration statistics for various top level domains.