may be varied within a relatively wide range where the seal structure 14 is a sponge like foamed compound the following recipe in which the ingredients are represented in parts by weight will provide satisfactory results insofar as the invention is concerned ______________________________________vistalon 6505 epdm sup 1 100stearic acid 1zinc oxide 5fef carbon black n550 30srf carbon black n774 60whiting 35mistron vapor talc sup 2 35sunpar 2280 oil sup 3 80sulfur 2 00kempore 150 blowing agent sup 4 6 00tellurac rodform accelerator 1 00methyl zimate accelerator 1 25butyl zimate accelerator 1 25thiate u dibutylthiurea sup 5 2 50______________________________________ sup 1 exxon chemical co sup 2 cyprus industries sup 3 sun oil co sup 4 uniroyal chemical co sup 5 elastochem co while foamed sponge compounds such as that shown in the preceding recipe are often preferred other non foam compounds of the types well known in the art may also be used for the seal structure when such recipes are employed the material produced which is typically softer than that used for the carrier and root portions may advantageously also be used for the tip portions of the fingers an example of a typical recipe in which the ingredients shown are in parts by weight is as.