Smitty... I noticed your earlier post on pumps, and decided to jump in a little in the hopes others will provide feedback on these new K-pumps.
With just a little reasearch, and having 10+ years guiding and river running (although I haven't owned a single pump), I've been able to come to the following conclusions:
1. Cheap pumps (foot, double-action wonder pumps) suck.
2. Carslon/NRS/PVC-based single-action high volume pump models rule.
3. K-pumps are piston-style tough ABS plastic double pumps with decent volume to make them good top off pumps, and the 400 model has enough volume (1.3 gals./stroke- but spendy at $175!!!) to get a raft fully inflated but......
4. K-pumps are a single-piston pump that requires the user to pull out and push in on the handle, using the hands and arms only. All well and good, and "effortless" according to their website. But this action, over time, would seem to be inherently fatiguing on the arms and hands. IMHO, the up-down action of a stand-up high volume pump using the entire upper body is much more energy-efficient. Anyone with experience with k-pumps feel free to refute this statement.
I'm in the process of buying my first raft, and I'm definitely getting an NRS 5" pump (and doing my best to never have to fully inflate my new 16' boat!!!)
Hope this helps! -Tyler
ps: the 100 is the smallest version- the 400 is the largest.