This adapter has a 45mm 24tpi female thread (~1mm pitch) for screwing onto the rear of a Mak-Cass telescope, and converts to a 2" 24tpi male thread for attaching to 2" filters, field reducers etc. commonly used with Schmidt-Cassegrain (SCT) telescopes.Suggest printing at 0.1mm layer height. (Thread generation routines by Freakin' Sweet Apps, LLC ([email protected]/* <![CDATA[ */!function(t,e,r,n,c,a,p){try{t=document.currentScript||function(){for(t=document.getElementsByTagName('script'),e=t.length;e--;)if(t[e].getAttribute('data-cfhash'))return t[e]}();if(t&&(c=t.previousSibling)){p=t.parentNode;if(a=c.getAttribute('data-cfemail')){for(e='',r='0x'+a.substr(0,2)|0,n=2;a.length-n;n+=2)e+='%'+('0'+('0x'+a.substr(n,2)^r).toString(16)).slice(-2);p.replaceChild(document.createTextNode(decodeURIComponent(e)),c)}p.removeChild(t)}}catch(u){}}()/* ]]> */))