Ray-O-Vac 3 in 1 Flashlight
Ray-O-Vac 3 in 1 signaling flashlight. Here's an ad from 1929 with the flashlight. It's #2 on the left and #2 on the right. You might need to zoom in to see it better, by making the text larger, or use a good magnifying glass. Below you can read what it says about the light in the ad, that I copied. My camera just can't zoom in on it good to make it readable.
The Rayovac 3 color signaling flashlight. Independent switch for each color. Combination for all. Permits signaling or may be locked.
Here's a better look at the 3-1/signal light that is pictured in the ad. Notice the ad says nothing about being a 3 n 1 flashlight. All the 3 n 1 flashlights have the red, green and clear bulbs, with the 3 way switch. The early Franco had 3-1 printed on the end cap, and is the only one called a 3 in 1 as far as I know.