<p><strong>Model R230</strong>&nbsp;&nbsp; 15mm, 18x Quadruplet lens.<br />
<strong>Model R231</strong>&nbsp;&nbsp; 12mm, 10x Doublet lens.<br />
<strong>Model R232</strong>&nbsp;&nbsp; 11mm, 6mm, 10x. 15x Doublet lens.<br />
<strong>Model R235</strong>&nbsp;&nbsp; 16mm, 10x Triplet lens.<br />
<strong>Model R236 &nbsp; </strong>14mm, 10x Doublet lens.<br />
<strong>Model R237&nbsp;&nbsp; </strong>12mm, 20x Triplet lens.<br />
<strong>Model R7520</strong> 18mm, 10x Triplet lens.<br />
<strong>Model R2450</strong> 18mm, 10x Triplet lens.</p>