Professional Gem Refractometer Plug-In - Easy to Read

RGM-PLUG - 1.31-1.81nD Range Plug-In Gem Refractometer   FINALLY!  A plug in Refractometer that will give you consistent light!  No more batteries and the no more bad light that comes from weak batteries! THE PLUG IN LIGHT SOURCE ALLOWS FOR A CONSTANT PERFECT STREAM OF LIGHT!  It is the easiest Refractometer to read on the market! Comes with easy to follow instructions in English!  Written by our staff, not converted from another language! Comes with a Gemstone Refractive Index Chart! Comes with 3.6ml of 1.800 Refractive Index Fluid - DOUBLE THE AMOUNT FLUID THAN OTHER SELLERS! PRODUCT SPECS: Range: 1.30-1.81 Refractive Index (RI)Resolution: +/- 0.01 RIAccuracy: +/- 0.01 RIDimension: 4.5" x 1.5" x 2.5"Weight: 400 GramsComposition: Sturdy, Portable Design made of die cast aluminum, not plastic like the GIA onesTHE LIGHT SOURCE: 36” inch corded 110 volt plug at 789nm.  The light source will not become hard to read when batteries grow weak!  It is a constant bright light!   Perfect for t