MRT-180 Handheld Refractor Manual Refractometer * Streamline design and sttractive appearance * Metal material and gorgeous color.A variety of colors to be chose * Easy operation:suitable for children,adolescents and adults * Easy to carry,suitable for all kinds of occasions * Self-check,do not need others’help * Professional website service, interaction,sharing,and vision data permanent preservation Suitable for Children, adolescents and audlts Color China Red(R), Sapphire(B), Harvest Yellow(G), Pink Drerm (P), Roland Purple(V), Titanium crystal Gray(S) Spherical range -12D to 6D Spherical degree wide interval 0.5D Spherical degree of tolerance ±0.25D Lighting LED backlight, and the light is uniformity, constant, not reflective and not dazzling Switch mode LED lamp touch switch, instrument will shut down automatically after three minutes’ shelving Power Three 7# batteries(AAA) Service Professional service website, Users can input personal vision information, Forecasts user’s vision direction according to historical data, Provide vision care knowledge and glasses reference information, etc. Net weight 299g Packing size 200mm(L)X100mm(W)X65mm(H)