Verithin Gruens were mainly 17j adjusted 5, 6, or 8 positions. The various Semithins were commonly 15j rarely up to 19j and 4 adjustments including temperature. However, Dietrich and Fred were conservative with jewels and offered 5 position adjt. 15 and 16j Verithins of same quality as the 17-21j movements. Two are here. Madretsch marked 16j 1913 and Swiss marked 15j 1917 Verithins. Both not common. Both in Gruen marked gold fill cases and fine dials. Not cheap watches although less than 17j, but not much.