The AccliStick from Reef Gently is a a great idea to get a baseline drip rate for acclimating different sorts of fish. The very first day we worked at a fish store, one of the veteran fishguys showed us how to tie a loose knot in airline tubing to adjust the drip rate on acclimating newly imported fish. Besides adding a small gang valve to the end of the drip hose, very little else has changed in the functionality of how we get newly shipped fish from the bag to the tank.
The AccliStick works by being inserted inside airline tubing, and incrementally blocking the flow based on how far it is inserted. For example you might insert the AccliStick part of the way for hardy fish just brought back from the fish store, or all the way for delicate sailfin anthias you just had shipped to you from the Diver’s Den. The low-tech AccliStick only costs $5.99 but if you frequently order fish online or handle delicate species, you might consider Reef Gently’s digital method to adjust acclimation drip rate.