Abstract: A millisecond delay surface connector suited for explosive blasting operations is provided in the form of a flexible detonation transmitter tube having a length of about one half foot and more with a delay cap connected to each end of the tube. The tube provides a hollow elongated gas channel having the inside periphery of said tube coated with a layer of explosive for sustaining a percussion wave at high velocity along the length of the tube. Each cap includes an elongated tubular shell of rigid material having a closed terminal end portion, a layer of explosively inert material within the shell at the terminal end portion, a delay element within the shell and a detonating charge intermediate to said delay element and said explosively inert layer. The delay element is in propagative relationship with the tube and the detonating charge.

Abstract: A non-electric double delay borehole downline unit is provided for delaying transmission of an explosive signal down a borehole and also delaying initiation of the charge within the borehole after the signal has been received therein. The double delay unit comprises a length of flexible impulse propagating tubing having first and second ends and an impulse propagating hollow channel extending along the length thereof, a non-electric high strength blasting cap containing a first delay element connected to the first end for initiating a borehole explosive charge, an impulse amplifying and transmitting cap containing a second delay element connected to the second end and a protective block having a plurality of elongated apertures with one of said apertures fully and snugly receiving the amplifying cap therein.