In 2003 Shimano introduced "Dual Control" to mountain bikes, where the gear shift mechanism is integrated into the brake levers. This development was controversial, as the use of Dual Control integrated shifting for hydraulic disc brakes required using Shimano hydraulic disc brakes, locking competitors out of the premium end of the market. However, with their 2007 product line, Shimano moved back to making separate braking and shifting components fully available in addition to the integrated "Dual Control" components, a move to satisfy riders that wished to use Shimano shifting with other brands of disc brakes.