The ALPHA Twincur GEM In-Line Wheels for Straight and Beveled Edge of All Stones. Size: 6". Grit: 500. MAX RPM: 2,000. Connection: Snail Lock. Material: All Stones. Alpha® Twincur EG and ES series has established a reputation as the best tools to polish straight and beveled edges on granite and Engineered Stones/Quartz Surfaces. Now Alpha® has developed a new polishing system to save you time and money by combining these two systems into one. Introducing the Alpha® Twincur GEM for use on all types of stones. Available in a 5” and 6” diameter with a snail lock adapter (SFAT) to fit on most popular edge polishing machines. Produce high-quality straight or beveled edges with less tool inventory by using the Alpha® Twincur GEM. Now available with a Final Polishing wheel called “Tsuya” to achieve the highest possible shine!