This is an amazing general-purpose gardening tool. It is impressive how quickly a 10" deep trench can be made, even in difficult soils. Based on the design of a Swedish tool for fighting forest fires, it came to us from a customer who loved it for garden work.
Our version of the tool has several modifications to better suit it to gardening and yard work in general. We lengthened the handle to 39" and made it of vibration-dampening hickory. The 5" wide head is curved perfectly for use as a trencher; it loosens the soil and traps it in its basket-like shape for easy removal. The sharpened front edge, made from hardened carbon steel, slices through soil and roots. At only 3 1/2 lb, it is ideal for all sorts of trenching from simple drainage trenches to burying hose, rabbit-proofing fences (burying the bottom few inches) or even excavating transplant holes.
Much more intuitive and easier to use than a spade for these jobs, it substantially reduces back strain in them all.