The OPTIONAL Large Wand gives you the ability to read many coins in numismatic slabs as small as 1/4 oz, smaller than can be read on the pro unit with any other sensor. It is not possible to read coins under 1/4 oz in slabs typically. Raw coins as small as 8 mm can be read under the small bridge or with the small wand. The large wand is recommended if you deal with a lot of slabbed coins.
Get the best of both worlds. Sigma Metalytics products are great for coins & bullion but not Jewelry & Scrap precious metals. Kee is great for testing Jewelry & Scrap gold and platinum but doesn't test silver or test through numismatic slabs as Sigma does.