You need to find out rather or not the vendor has pics available of the product they are selling. When you're shopping personally, you have the option to look at merchandise close up, hold them in your hand, and study their texture. When you're shopping Xinyuan 10pcs/lot BTB16-600B BTB16-600BW 16A 600V TO-220 BTB16-600 TO220 BTB16 16-600B online, images are the closest thing to that there is. I would not recommend buying from any web based goods shop that doesn't present pictures of the product. You must research the online goods shop's shipping policy. How much is going to shipping be? Is it free of charge? If it's free, will it take an eternity to arrive? If I need to pay for it, when can I anticipate my purchase to arrive? These are all things you as a consumer should know, and you can usually easily find the answers to these questions simply by find a "Shipping Policy" or "FAQ" page on the site. Previous, but certainly not least, you should find out what forms of payment the web page accepts. This seems like it will be obvious, but I can't even count the times that I've found a wonderful quality merchandise on a site, only to find out that they don't accept any of the forms of payment I have offered.