Gain all the benefits of through-the-lens (TTL) loupes without the expense or delay of customization. TTL Easy Size Loupes are complete with four sets of interchangeable, progressively spaced lenses, each with an integrated, screw-in attachment for the Galilean magnifying loupes included. Simply measure your pupillary distance (PD) with the precision scale included. Select the lens pair that corresponds to your PD and quickly snap those lenses into the frame. Each lens has a threaded receiver for the Galilean magnifying loupes. Install the loupes and you are ready to go—in a matter of minutes, instead of days or weeks, for hundreds of dollars less! TTL Easy Size Loupes eliminate the weight and interference of hinged, clip-on loupes and significantly improve the field of view. Set includes a snap-in Rx lens insert that can be filled at your local optometrist, if needed. Replace the removable temples with the adjustable, elastic headband for all-day comfort and security. TTL Easy Size 3.0X Loupes come complete with frame, adjustable strap, optional elastic headband, snap-in prescription lens insert, storage case with soft drawstring bag, cleaning cloth, one pair of 3.0X Galilean loupes with protective covers, PD scale, and four sets of lenses: SS (56mm PD), S (58mm PD), R (60mm PD) and L (64mm PD).