Well, here's a copy pasta for you, that I found around, replying bascially to the same question as yours:
Short answer, yes, basically, but you can't call them "cannabis grinders", or even "herbal cannabis grinders". Call them "herbal grinders", instead, and you'll be golden. In fact, be certain that the words cannabis, pot, bud, grass, green, chronic, hash, hashish, (etc) never show up on your site. Even their presence in customer testimonials can cause trouble for you.
You seriously want to stick to the, shall we call it, sanitized nomenclature. Tommy Chong had his inventory seized, was sentenced to 9 months in federal lockup, and issued a hefty fine because, basically, he didn't play by the rules and sold "bongs" instead of "water pipes". Likewise, never refer to kief, kiefer, or kiefing. Refer instead to pollen, as in pollen sifter instead of kiefer/kiefing box.
When you're talking about the products you want to sell, there's a lot of very slippery legal gray area, and if you don't use the syntax that allows you to operate in that gray area, then you'll get slapped. Read up on Operation Pipedream and Operation Headhunter for an example of government crackdowns on possible paraphernalia sales online. Be very careful out there!