When sourcing transfer tape, the most critical factor is the tack level (Low, Medium, or High). Medium-tack is the industry standard for most adhesive vinyl, while High-tack is essential for glitter or textured vinyl. You should also verify the liner type; tapes with a grid-patterned backing significantly improve alignment accuracy for end-users. Additionally, ensure the material is clear (transparent) for precise layering and has residue-free adhesive technology to prevent ghosting on the final substrate.