https://www.ebay.com/itm/305300436363

Vintage Imperial card catalog for 5 x 8" index cards

Listed for auction in December 2023. After 14 bids, sold for $158.50 on 2023-12-11. Seems rare for these to actually sell by auction.

Cost per drawer: $39.63.

https://www.etsy.com/listing/1571702826/vintage-alphabetized-index-cards-5x3

Imperial apparently made card dividers in addition to card catalogs.

https://www.etsy.com/listing/1378872932/antique-imperial-large-card-catalog-wood?show_sold_out_detail=1&ref=nla_listing_details

Another large format card index from Imperial.