Beta 1.0
Sex toys such as the strap-on dildo substantially lower (on or near the vaginal opening) rather than higher up, has a continual waistband that is not part of the dildo mount or backing, with a V-shaped pair of straps in the front, and either the single strap between the legs or the two straps around the thighs. The former of these is called a 3-strap, and the latter a 4-strap, however most of the aspects of their design and use (such as a strap over the anus, etc) are the same as 2-strap and 3-strap harnesses, respectively.
Dildos Harnesses are not limited to the crotch, and indeed many types are available for other body parts. A popular one is a thigh harness, which attaches a dildos to the wearer's thigh or other part of the legs or arms, though this is much less common, allowing for many unique different positions, as penetration is no longer limited to what could be done with a penis. Another unusual design attaches a dildo to the chin of the wearer, allowing vaginal penetration while performing cunnilingus.
Furniture, beach balls, and other objects Harnesses are available to attach dildos to just about any household object, allowing for many creative uses. A dildo could be attached to a chair, bed, or any other item of furniture, and penetrate someone during other activities, with or without a partner. Another item which can be used for dildo penetration, while not technically a harness, but worth mentioning, is an inflatable ball, usually 9 to 18 inches diameter, made of sturdy rubber designed to support the weight of one or two people, with an attachment for a dildo on it. This allows many unique positions, such as double penetration for a woman by laying face down on the ball for vaginal penetration while her partner penetrates her anally doggy style, which is much more effective than a solid object due to the "bounce" of the ball. These inflatable balls are also quite popular for solo use.