Check the listing for details. Criterion S-1-1/2 Micrometer 1/2" Boring Head .001 DIV CAT40 Command Tool Holder. Condition: New – Open box. Listed at 379.99 USD. We have these 100% perfect units for sale here as singles (You get FREE Shipping after 1st one purchased), but we do also have many more CAT 50 and Cat 40 tool holders for sale in our EBAY store,, But you will get FREE Shipping Cost After the 1st one purchased. Our inhouse Veteran Machinist inspected these units and says they are 100% perfect working order. He said that they're perfect. This Boring Head holds a 1/2" round (boring Bar)tool from the bottom Hole. The one on the Left also has an adapter down to 1/4" size.If you purchase just 1 unit, please tell us what one you are choosing., We do have other Cat50 and Cat40 Tool Holders for sale, we can combine shipping. Check our EBAY Store for more.