They often burst at the seams after a few uses, although they are commonly given as gag gifts and therefore many may not be used at all.
In Russia for some years the Bubble Baba Challenge humorously featured participants river rafting on blowup dolls as a matter of entertainment but in 2013 the race was cancelled on "health and safety" grounds.
By the 1970s, vinyl, latex and silicone had become the materials most frequently used in the manufacture of sex dolls; silicone in particular allowed a greater degree of realism.
A 1982 attempt to import a consignment of sex dolls into Britain had the unintended consequence of ending the law against importing "obscene or indecent" items that were not illegal to sell within the UK.
These dolls usually have an articulated PVC or metal skeleton with flexible joints that allows them to be positioned in a variety of positions for display and for sexual acts.
Silicone or TPE dolls are much heavier than vinyl or latex inflatable ones (which consist mostly of air), but are roughly half the weight of a real human being of comparable size.
They have an artificial and typically crudely designed vagina or penis, but due to their affordability many users are willing to overlook their shortcomings.
The parts are sometimes vibrating and may be removable or interchangeable.
Some of the first sex dolls were invented by Dutch sailors in the seventeenth century who would be isolated at sea during long voyages.
The manufacturing process causes most latex dolls to be delivered with a fine coating of zinc oxide covering the skin, which is usually removed by the consumer by placing the doll under the shower.
Otherwise, latex is an inert and non-toxic natural material; although a small percentage of users may discover a latex allergy.