1000-lb engine stand. I think it's an Ironton brand from Northern Tool. Head rotates. The pin that locks it in place is missing but any relatively close sized bolt will do the job. The wide spacing of the front wheels makes it a little bit of a pain to use with an engine hoist but makes for a super stable platform to work on the engine and it's not going to tip over like one of the three legged ones when you try to move it around.
