Customer service. The on line person was willing, but had limited experience (trainee). The phone number provided led to a voice mail that was returned once by email, but on other occasions rang forever. When I mentioned this in an email exchange, I was told, "they are very busy". Also of note, I was informed twice that the Thule probar was incompatible with the Hullavator system. The Hullavator's installation manual has installation instructions for the probar. I found the correct information on a competitor's site. Fortunately, you had what i wanted in stock and at a better price. I like your site's layout and ease of use, and everything i ordered got shipped same day and arrived ahead of schedule.