You need to find out rather or not the vendor has images available of the product they can be selling. When you're shopping face-to-face, you have the option to look at merchandise close up, hold them in your hand, and study their texture. If you are shopping MJ10021 60A 250V NPN POWER TRANSISTOR TO-3 2-Pin TO-204A* Imported Chip online, photos are the closest thing to this there is. I would not suggest buying from any on-line goods shop that doesn't display pictures of the product. You need to research the online goods shop's shipping policy. How much should shipping be? Is it no cost? If it's free, will it take an eternity to arrive? If I must pay for it, when can I expect my purchase to arrive? These are all things you as a consumer ought to know, and you can usually easily find the answers to these questions simply by find a "Shipping Policy" or perhaps "FAQ" page on the site. Previous, but certainly not least, you should find out what forms of payment the site accepts. This seems like it may be obvious, but I just can't even count the times that I've found a wonderful quality merchandise on a site, only to find away that they don't accept any of the forms of payment I have obtainable.