Problem for someone who's pushing 90, say

SPEEDGUN

This tool might be tricky to handle if your reflexes aren’t what they used to be—it’s often found in competitive shooting matches.

This clue plays on the phrase "pushing 90," which usually means nearing 90 years old—but here, it hints at pushing a speed gun (like a radar gun) to measure how fast something’s moving. The word "problem" suggests the gun might be malfunctioning or giving trouble, making "SPEEDGUN" a clever misdirection. It’s a pun mixing age-related slang with a literal object tied to speed.