MC211 corrective lenses can be inserted into the TUSA M2004 Intega mask as well as TUSA M211 Freedom One masks. For Minus correction available in 0.5 diopter increments from -1.0 to -8.0 For Plus correction available in 0.5 diopter increments from +1.0 to +4.5 For Reader correction available in 0.5 diopter increments from +1.0 to +4.5 Lenses are sold individually.