When applied properly, an SPF 15 filters out 93 percent of UVB, SPF 30 filters 97 percent and SPF 50 filters 98 percent. SPF 15 is good enough. According to The Skin Cancer Foundation, most sunscreens with an SPF of 15 or higher do an excellent job of protecting against UVB.PF10-15 is good enough for me as my skin is allergic to higher SPF for you need to add chemicals onto the product in order to achieve a higher SPF.
TEXTBOOK AND COURSE BOOK POLICY. Desk copies | Course use examination copies | Ordering | Course adopted books as electronic downloads . Desk Copies. Desk copies are complimentary books sent to professors who have already adopted the book for a course. To request a desk copy, professors can send an e-mail to our customer service vendor, the Chicago Distribution Center (CDC), at orders@press.uchicago.edu.
Before you submit your desk copy request, please note: 1  This form is for US orders only. The Canadian Academic request form is located here. 2  Desk copies are for adopted required titles only. 3  Desk copies will not be sent until your bookstore has ordered the texts. If you wish to review a title for possible adoption, please complete our examination copy form. You must fill in the bookstore name and telephone number or your order will not be processed. Only one desk copy is available for every twenty copies of each title ordered through a bookstore for course use. However, requests for a single desk copy for seminars and graduate courses with a minimum enrollment of ten students will be honored.