银样镴枪头

idiom

something that looks impressive but is actually useless; deceptively attractive but worthless

Originating from Wang Shifu's 'The Romance of the Western Chamber' (西厢记). The phrase likens something to a gun head made of pewter (镴) that merely looks like silver (银)—attractive in appearance but lacking in substance. Often used to describe people who appear capable but lack real skill, or objects that look good but perform poorly. Carries a derogatory connotation.