A chemical vapor deposited, \u03b2 phase polycrystalline silicon carbide having a high thermal conductivity and reduced stacking faults. Various monomers, resins and methods for preparing such cross-linked polyethers are also disclosed. The PFTE core or sheet is bonded on both sides by a thin layer of pliable tacky polyurethane mix. In some aspects the signal may comprise a digital signal. The support also has a releasing mechanism preventing an action of the spring on the second jaw, thereby allowing the movement of the blade away from the hole.