The utility model provides a closed -type fixture includes: the fixture main part, with the cooperation of fixture bulk phase, divide the fixture upper cover of body coupling in the fixture main part, wherein, the fixture upper cover links together with the fixture main part and constitutes a circular inner chamber, and fixture main part and fixture upper cover lean on the edge of quasi -circular inner chamber to be provided with a plurality of evenly distributed's recess, with the recess one -to -one to set up a plurality of can the breaking out through the pivot pivoted in the recess, wherein, the recess and the looks adaptation of breaking out, set up in the recess lateral wall, and the elasticity preforming that touches mutually with the lateral wall of breaking out. Block steel cap during operation at the closed card, unload the piece and can automatic size according to the steel cap independently adjust, reach unload the piece all the time with the suitable cooperation of steel cap, during the loading atress, the closed card is the atress evenly, convenient to use does not receive the restriction of steel cap appearance, has increased the feasibility of operation, improved the circuit the availability ratio, eliminated hidden danger, ensured power equipment's safe operation, increased power supply quantity, have certain economic benefits.