Please use only one item.  

Primer: As a chemical product, It helps the glue to dry faster and improves adhesion strength better and stronger. 

Pre-Treatment : It removes oil, dust and makeup residue on your lashes, so it helps false lashes stick to natural lashes well. 

Both items are used for the purpose of helping glue's adhesion. It would have a great influence on adhesion during summer with unstable environments such as high temperature and humidity. 

*Caution*

Primer should be used only for false eyelashes and please dry it completely before applying the eyelash extension ( Do not apply Primer on natural lashes). 

Pre-treatment is recommended to use for false eyelashes as possible. If you need to use pre-treatment for natural lashes, please let the person seat on the chair, and please take careful handling and keep pre-treatment out of the eyes.