From the product description, check product page for current description, price and availability:

What is a BeerGun? It is an easy way to fill beer bottles with sediment-free carbonated beer from a kegging system without excessive foaming.

Beer foam is caused by a sudden change in pressure. Unlike awkward counter pressure fillers, the BeerGun does not pressurize the bottle to avoid a sudden change in pressure when filling, but instead relies on a very gradual reduction in pressure from keg pressure to the open air. By avoiding design features like ball valves and sharp bends in the flow path, the BeerGun gently reduces pressure on the carbonated beer as it flows through it, with the result being the cold carbonated beer that flows out has minimal foam, while still containing carbonation. A purge button behind the trigger lets you first flush the bottle with C02 before filling if desired to eliminate oxygen in the capped bottle.

What matters is the BeerGun is easy to use, and makes filling sediment-free beer bottles from a keg an easy job instead of a chore. For successful use, beer must be below 37° F. and beer bottles must also be cold.

To use the BeerGun, you will need a kegging system filled with carbonated cold beer and C02 regulator. Hook the included 10’ of beer hose up to your ball or pin-lock barbed beer keg fitting. Now provide 5’ or so of gas hose, and a Q12 hose barb (both not included) and screw it into the base of the BeerGun and attach the gas hose. Hook the other end of the gas hose to a spare hose barb on your regulator. Now pull the trigger to easily pour carbonated beer into bottles. Cap quickly to avoid carbonation loss, and you are done. The BeerGun includes beer hose, a brush for the barrel, gas hose and connector, ball lock beer connector for your keg, and detailed instructions.

From the product description, check product page for current description, price and availability:

Compact ball lock spunding valve features a 0-30 PSI gauge and now features an adjustable manual pressure pull ring relief valve (adjusts from 0-15 PSI). The adjustable manual pressure release can be removed, and a corny keg pressure relief valve installed in its place. The gauge features a standard DuoTight 8mm stem, and can be replaced with our DuoTight gauges, like our items C18, Z97, and E69 if desired.

Lots of ways to use this and upgrade it. If you want more accuracy than the manual adjustable spring loaded relief valve, you can upgrade with our item C16 DuoTight Blowtie valve, which has a rubber diaphragm valve which will always be more accurate at low pressures than the included spring loaded adjustable relief valve. If you do this, you will also need DuoTight Joiner, item number C70.

You can also replace the manual adjustable relief valve with preset keg relief valves like our item G65 (17 PSI) or B54 (0-30 PSI).