Because the Custom1Rar uses high-poly counts (often 150k+ tris), you may need to enable "Experimental Mesh Limits" in your game engine settings to prevent crashing.
If you want to dive deeper into this topic,rar files from unverified third-party forums.
: If the custom item appears "invisible" or "checked" in-game, ensure you have the "Mesh" file, which is often required for custom outfits to display correctly.