Nelson Vergel
Founder, ExcelMale.com
I really like this one. It keeps vials cool for about 1.5 days.
http://smile.amazon.com/gp/product/B000VD3BX4?redirect=true&ref_=cm_cr_ryp_prd_ttl_sol_18
http://smile.amazon.com/gp/product/B000VD3BX4?redirect=true&ref_=cm_cr_ryp_prd_ttl_sol_18