Does the door come prefinished?

Yes. It arrives fully painted white, so it can be hung without a separate paint step. Touch-ups at the edges may still be needed after trimming.

What size opening does it fit?

The door is 36 in. wide by 84 in. tall. The opening and track need to be checked against that size before installation, since the included hardware is matched to the door.

No. It is an MDF composite door with a six-panel layout printed on both visible faces. That makes it lighter and more stable than solid wood, but less resistant to knocks and moisture.

Can it be used in a bathroom?

It is described as an interior door. MDF composite swells when it takes on moisture, so a damp bathroom is a poor fit; a closet, pantry or laundry room suits it better.

The bi-fold door unit and the 43 in. sliding hardware assembly. Hinges and track parts come with the hardware; handles and trim are not mentioned.

Can the door be trimmed to fit?

MDF composite can be trimmed, but the painted finish and printed face end at the cut, so edges need sealing and repainting. Measure the opening first to avoid cutting.