A sample holder for electron microscopy of air-sensitive samples for use in electron microscopy incorporates a housing and a closure assembly. The closure assembly comprises a lid comprising at least one closure arm receiving portions recessed within a flat, planar upper surface thereof. The housing comprises one or more closure arm(s) corresponding to one or more closure arm receiving portion(s). In a fully closed position, the closure arm(s) share contact with the closure arm receiving portion(s). The lid is flexibly coupled to a motor cover plate which can be actuated by a motor assembly configured to open and close the lid. The sample holder also includes an elevator assembly with a vertically adjustable sample stage which sits below the lid. The sample stage is vertically adjusted by actuation of a bellows assembly which sits beneath the sample stage.