  Single W and single gamma productions which are sensitive to the trilinear
gauge coupling WWgamma have been studied at LEP. It isshown that single W
production has particular sensitivity to the "anomalous" magnetic moment Kgamma
of the W boson, complementary to WW production at LEP and Wgamma production at
hadron colliders. The invisible decay of W boson has been searched and the
limit on the invisible decay width of 27 MeV at 95% C.L. has been obtained.
