AutoBild has tested the HEYNER® WheelBlock Pro and named it the test winner among steering wheel claws.
"In addition to being easy to use, Heyner's steering wheel claw impresses above all with its excellent safety. Its five stable number wheels could not be bent apart by a professional in order to insert a so-called scanner with which the right combination can be determined."
"To pick the lock you would have to flick it open ..."
(Source: https://www.autobild.de/artikel/lenkradkrallen-im-test-49826.html)
to the whole test article on autobild.de