While a mobility scooter eliminates much of the manual strength problems of an unpowered wheelchair, its tiller steering mechanism still requires upright posture, shoulder and hand strength, and some upper-body mobility and strength, although the delta tiller goes some way to alleviate these constraints. The arm-rest mounted controller typical of powerchair designs may be more suitable for many users. Scooters also have fewer options for body support, such as head or leg rests. They are rarely designed for ease of patient transfer from seat to bed.