Abstract: An insulator-jack for replacing damaged electrical insulators in a string of insulators comprises a pair of threaded rods disposed in substantially parallel relation to one another, a pair of coplanar spaced-apart insulator clamping collars, each being connected to opposite ends of the rods by a pair of lateral arms, wherein one of the insulator clamping collars is movably positionable along the threaded rods by a pair of ratchet members to selectively vary the distance between the two clamping collars. The non-movable clamping collar is provided with an upwardly and inwardly projecting safety tongue which engages the connection between the insulator clamped within the collar and the next-above insulator in the string, and is also provided with inward projections along the internal periphery to securely engage the insulator and thereby prevents slippage of the insulator.

Abstract: A high energy explosive composite which comprises(1) from about 2 to about 30 weight percent of an energetic polymer matrix f a urethane which is the reaction product of(a) a hydroxy-terminated prepolymer of the formula ##STR1## where R is --CH.sub.2 CF(NO.sub.2).sub.2 or --CH.sub.2 C(NO.sub.2).sub.2 CH.sub.3 ; A is --CH.sub.2 CH.sub.2, --CH.sub.2 OCH.sub.2 --, or --CH.sub.2 OCH.sub.2 OCH.sub.2 --, and n>1, and(b) a polyisocyanate which is used in an amount sufficient to supply from about 0.8:1 to about 1.5:1 isocyanate functional groups for each hydroxy functional group;(2) from about 8 to about 20 weight percent of an energetic plasticizer; and(3) from about 50 to about 90 weight percent of an explosive;wherein the energetic plasticizer and explosives are uniformly dispersed throughout the energetic polymer matrix.