Mountain bikes are available in tandem configurations. Tandem and sociable frames support multiple riders. These produced a high speed with four engines clutched together in tandem pairs. This introduced a dual hollow charge "tandem" warhead to defeat explosive reactive armour. The trainer has seating for two pilots in a tandem arrangement. The missile has a bicalibre body, consisting of two stages in a tandem configuration. These ionization techniques are used in conjunction with mass analyzers such as tandem mass spectrometry. For example, Galectin-8 has seven different mRNAs encoding for both tandem and dimeric forms. Armenia has favorable conditions for paragliding in independent and tandem flights. Wraparound boosters will usually generate higher drag than a tandem arrangement. An important application using tandem mass spectrometry is in protein identification. Patents related to tandem bicycles date from the mid 1880's. This can lead to variations in the tandem postures. The two often appear at conventions in tandem. They were seated in separated tandem cockpits.