Retaining apparatus for expansion cards

A retaining apparatus comprising:

• a first bracket comprising a first sidewall and a second sidewall parallel to the first sidewall, the second sidewall defining a slide slot;
• a second bracket comprising two side plates parallel to each other, wherein the side plates are slidably attached to the first sidewall and the second sidewall, respectively, one of the side plates forms a flange slidably inserted in the slide slot of the second sidewall;
• and
• an operation member comprising an operation portion, a mounting piece and an engaging portion extending from opposite sides of the operation portion, the mounting piece is fixed to the second sidewall, the engaging portion contacts with an inner surface of the second sidewall facing the first sidewall;
• wherein the first bracket and the second bracket are operable to be moved toward each other for retaining a first size expansion card, the flange slides in the slide slot, until the flange engages with a left inner sidewall bounding the slide slot, a left end of the engaging portion engages with a right end of the flange;
• and
• wherein the operation portion is operable to be pressed away from the second sidewall to release the left end of the engaging portion from the right end of the flange, the first bracket and the second bracket are moved away from each other for retaining a second size expansion card greater than the first size expansion card in length, the flange slides in the slide slot until the flange engages with a right inner sidewall bounding the slide slot, the engaging portion is restored to contact with the inner surface of the second sidewall, a left end of the engaging portion engages with a right end of the flange.