denmyos for a shock pump, I would check to see how much air your shocks can handle. Then buy the pump that will meet that psi. If your shock will go beyond 300psi, then get the 600psi pump. 600psi is a lot of pressure and unless you weigh a lot with all of your gear you ride with, then chances are you will not need the 600psi pump. The max pressure on your shock should be on a label or scribed somewhere on your pump. If not, look it up online. Hope that answers your question.
My girlfriend weights 800 LBS and rides a $12,000 carbon fibre S works mtb, we had to buy a special 1000 PSI pump for her big juicy fat cunt but sadly as soon as she sat down on the bike it crumpled under her fart box … Specialized said they wouldn’t warranty it and they were happy it broke , it likely saved her life before she seriously hurt herself even more than she already has by being a complete utter fat disgusting filthy ass pig .