These are the first generation of Soviet SSBNs, contemporaries of the 627 SSN (November class) and the Project 659 SSGN (Echo class). All three shared the troublesome VM-A dual reactor system. The Hotel I was equipped with the D-2 launch system and the R-13 missiles. The short range (350 nm) R-13 had to be launched from the surface, riding up on an elevator out of the missile silo, stabilized by hold down arms. The later Hotel II (658M) had the D-4 underwater launch system and the longer range R-21 missile. Both missiles were liquid fueled with toxic storage propellants and oxidizers. A parallel diesel submarine SSB was the Golf I and Golf II, which had the same missiles and launch systems as their Hotel I and II counterparts.