Looking for a floor pump for my fatbike and gravel bike
lenzye has decent variety. But not sure which to go with
do I get the one that has the extra canister for the tubeless tires
i pretty sure I need a high volume pump. which ever one I by
any recommendation on model and brand
i was leaning towards lenzye

are you riding tubeless?

A high volume pump would be better for either a gravel or fat bike. A boost chamber makes it easier to set up tubeless tires. I have a high pressure pump with a boost chamber and it makes setting up tubeless tires road or gravel a breeze. When I received my Canyon Grizl last February I did the tubeless conversion in about 15 minutes for both wheels. However a high volume pump would not have a high pressure gauge so it would be easier to get the lower pressure needed for high volume tires at the correct setting. My high pressure pump's gauge isn't very accurate at the 35 psi I need for my gravel tires. A high volume pump would also deliver enough volume per stroke to make setting up tubeless easier even without the boost feature

The high volume pump or high CFM, is only really needed if you let your big wide tires go flat often and you have to pump them all the way up again. Perhaps they are useful for tubeless setups, but I'm thinking there are other ways around that. IE, set the tire beads in the bead seat of the rim before trying to pump them up.

For just topping your tires off, any floor pump will do. The simpler usually being less expensive and will last longer.

I use a standard floor pump for my fat bike. The effort to fill a 27.5x4.5 to 6.5 lbs is tantamount to a 700x32 to 85 psi. If you are going tubeless then get one with a boost chamber. Any quality pump will be fine.

I've been using a Versair floor pump by Planet Bike for about the last 21 years. Works very well. Can put air in on the downstroke or both ways depending upon the setting. Has a dual head for both presta and schraeder valves. I use it for both road bike and mtn bikes. No problem inflating to 120lbs if that is what you like.

Silca Pista Plus is the on that I settled on. Retrofitted with a LOOONG hose, Silca analog gauge, Hiro chuck. Near perfection. Smooth as glass action. Accurate high pressure easily obtained. Rebuildable, lifetime of service. All parts are readily sold by Silca or their distributors. I have a supply of hose that equals the factory but can be cut to any length. I sell this with Oetiker clamps if anyone is rebuilding or modifying their Silca pump.