Look for "zipper garages" or soft internal backing. This prevents the cold zipper from touching the skin or snagging chest hair and jewelry. Review Template
Does the zip stay closed under pressure? A high-quality full-zip should have a "stay-put" locking mechanism to prevent the zipper from sliding down during movement. busty gfzip
Note if the material "sucks everything in" without feeling constraining. Reviewers of Girlfriend Collective often highlight that the right amount of compression prevents rolling or sliding. Look for "zipper garages" or soft internal backing
Be specific (e.g., "Perfect Support for 34G—No Zipper Slip!"). "Perfect Support for 34G—No Zipper Slip!").