Platypus GravityWorks vs Katadyn BeFree Gravity: Which to Buy

The second reservoir is the whole product. Most gravity filters, the BeFree Gravity included, dispense into whatever you hold under the hose. The GravityWorks 6.0L filters into its own 6-liter clean bag, which means water is banked. At a group camp that changes the evening: one trip to the creek, one hang, and the cooking water, the drinking water, and the dishwater are all sitting clean in a bag with a shutoff clamp. Platypus lists the full six liters in under four minutes at 1.75 L/min.

The costs are real. About 12 oz is four times the weight of a squeeze filter and about double the BeFree Gravity; the 0.2 micron pore is coarser than Katadyn's 0.1 (both cover bacteria and protozoa on listed claims, neither viruses); and at about $155 it is the most expensive filter in our guide short of a purifier. For a solo hiker it is the wrong tool. For a family of four at a lake camp, or a guided group, it is the right one and nothing else comes close.

Take the BeFree bottle's element, hang it from a 3-liter bag, and you have this. The BeFree Gravity 3L uses the same 0.1 micron EZ-Clean hollow-fiber element as the bottle, rated by Katadyn at up to 2 L/min and 1,000 liters, on a collapsible TPU bag with a hang loop and an output hose. Fill it, hang it from a branch or a trekking pole, hold a bottle under the hose. At a listed 6.4 oz it weighs about half the GravityWorks and packs flat when empty.

The element carries the BeFree family's known trade: it flows fast when clean, it cleans by swishing, and it cannot be backflushed, so silt loss is permanent and the 1,000-liter rating is optimistic in turbid water. Against the Platypus, which backflushes by lifting a bag and lists 1,500 gallons, the Katadyn is the shorter-lived system. Against carrying no gravity filter at all, it is the cheapest, lightest way to stop squeezing.