Can I have clips? Yes, but is there a charge for the clips. How do the units stay on? Either with clips, tape or bonding (glue). What's better, clips, tape or bonding? They all work well, it's just a matter of personal preference. What is the different base materials? Some are monofilament. Some are mono mesh, and others are polyurethane. Is the unit sent uncut? Yes. If you would like us to cut the unit in, there will be an additional charge for that. Can I get the unit with or without gray hair? Yes. What is the density of the unit? In most cases, medium. How long will it take after I order to receive the unit? In most cases 3 to 4 business days. How long will the unit last? Under good conditions, 2 to 3 years. Please send your questions to FAQ@HairOdyssey.com