The photon torpedo was the first designed to work at warp speed has been the weapon of choice for warp speed combat for over a centery. It's distructive force comes from a matter/antimatter reation upon impact with it's target.

SIZE: 2.1 x .76 x .45 m
DRY MASS: 186.7 Kg
RANGE LIMIT: 15 Km - 4 050 000 km (From Starships At Warp)
WARP SPEED: 110% Of Warp Factor Of Firing Ship
SUBLIGHT SPEED: Up To A 75% Higher Velocity (Maximum Velocity = Initial Velocity + .75 × Initial Velocity/ c {Or Vmax = Vi + .75 Vi/c)
WARHEAD: 1.5 Kg Matter/Antimatter (Avg.)
DEVELOPED: 2262
OPERATIONAL SINCE: 2264
YIELD: 175 Isotons