Levitating Cube

I tried to do a simple exporting test with Blender to source, and everything came around eventually but in actual Garry’s Mod, the box is floating mid-air. Here is my .QC file;



$modelname		"Cube.mdl"
$body mybody		"Cube.smd"
$cdmaterials		"models/weapons/parts"
$sequence idle		"Cube.smd"
$collisionmodel 	"Cube.smd" { $concave }


Any ideas for the problem?