The last of the 35mm cameras in my NaBloPoMo. Unless I change my mind that is. Anyway both are 1950s and 1960s 35mm rangefinder cameras. The Petri 7s was introduced in 1963. It was made in Japan and had built in metering. The Tower 51 is older. It was introduced in 1954. The Tower line of cameras was Sear's house brand. They were not actually made by Sears. Instead, they were made by a large variety of manufacturers across the globe. The Tower 51 was made in Germany. Its a nice simple rangefinder. Both provider nice examples of mid-range consumer grade cameras of the 1950s and 1960s.