Take the guesswork out of "matching the hatch" - use the Stomach Pump to be sure you're using the right fly.
The flies in the air are not always the ones on which the trout are feeding. Nothing is more frustrating than having feeding fish ignore your fly.
Pump your first fish and find out exactly the fly on which the fish are feeding. The stomach contents are not messy, and the flies are easy to recognize.
Small taper diameter won't injure fish, easy to use.