Feld ERG trial lens set
Compact and light weight,
Specifically designed for the electroretinogram test,
Fixed with metal ring, durable and reliable;
aluminum carrying case.
20 pcs lens for standard version,
Sphere in concave: 1D to 10D with 1D as step value;
Sphere in convex: 1D to 10D with 1D as step value;
40 pcs for Plus version.