Custom Invisible Clear RetainerImpression Kit Size Guide Custom invisible clear retainer. This appliance is not meant for closing gaps or realigning teeth. Custom Designed: Custom lab made from your impressions. Impression Kit Included: One impression kit is included per customer. Each impression kit includes 1 try to do your impression. If you feel you will not be good at it or want more tries, you can order extra putty or impression kits here to add to your order. Light &