Related Clues:

• Bass boat feature, sometimes
• Scientific breakthrough of the '30s
• Sub locator
• Bat abode
• Plane-tracking device
• Pitching coach's aid
• Speeder snagger
• ___ gun
• Gauge of heat or light, e.g.
• Leadfoot's nemesis
• Echo sounder
• Gun at a ball game
• Air-traffic aid
• Electric eye, for one
• Sub sensor