<https://www.billingboatsusa.com/product/pkn321610a-retractable-safety-knife-10a-grey/#product>
<http://schema.org/description>
"• PKN3216/10A\r\n• 5cm ruler on the back\r\n• For fine angle cuts &amp;amp; precise trimming\r\n• One per pack from choice of 4 scalpel blades"
<https://www.billingboatsusa.com/product/pkn321610a-retractable-safety-knife-10a-grey/>