The archetypal, often copied but never surpassed, benchmark of bipods from Harris Bipods. This model has notched legs with an adjustment range between 15 - 23 cm (6" - 9") and is fixed i.e. non-swiveling.
Height-wise, this bipod represents the lowest available. The true height straight down from the fore-end is 14 - 20 cm (5.5" - 7.9") and it's most suitable for bolt-action rifles and others without a tall magazine, off the bench or from a low prone position.
The bipod attaches to an ordinary sling swivel stud and folds forward out of the way when not in use. Stowed legs are kept firmly in place by sturdy spring returns. When deployed, the legs allow leaning into the rifle for better recoil management and a consistent point of impact.
The notched legs of Harris bipods (designated with an M in the model name) are spring-loaded and pressing a release button shoots them out to maximum extension. Adjustments are locked in at 18 mm (0.7") intervals and the bipod can be easily lowered by pressing the release button - the affected leg shortens and locks into the next notch automatically.
This type of adjustment is rapid and easy to use by reaching forward with just one hand. Hovering the rifle at the desired height and pressing the release buttons gets you close or exactly to the right setting without further adjustment regardless of surface irregularity. Additionally, the notches maintain the length without the possibility of slipping under recoil.
Many sources claim the notches to be spaced 25.4 mm (1") but we measured these ourselves and the closer 18 mm (0.7") intervals were a positive surprise. Thanks to the wonders of trigonometry, the effect to the actual rifle height is even smaller - you are unlikely to run into a situation where one setting is too low and the next one too high.