It looks like you’re referring to a “Tacky Flydrophobic SD Fly Box”—a specialized fly box designed for fly fishing. Here’s what I found about it:

Tacky Flydrophobic SD Fly Box (NOS)

Tacky Flydrophobic SD Fly Box Features:
1. Flydrophobic Material – The interior has a hydrophobic (water-repellent) coating, helping flies dry quickly and preventing rust on hooks.
2. Secure Storage – Uses Tacky’s signature silicone gel matrix to hold flies firmly in place, even when shaken or dropped.
3. SD (Super Durable) Version – A more rugged, reinforced version of Tacky’s original fly box, built to withstand rough handling.
4. Slim & Lightweight – Easy to carry in a vest or pack without adding bulk.
5. Clear Lid – Allows for quick visual identification of flies inside.
6. Variety of Sizes – Available in different configurations (e.g., SD Original, SD Large, SD Double Sided).

Why Fly Fishermen Like It:
– No more loose flies – The silicone grip keeps flies secure.
– Dries flies faster – The hydrophobic material helps prevent moisture buildup.
– Durable construction – Better resistance to cracks and impacts compared to standard plastic boxes.

Alternatives & Comparisons:
– Tacky Original Fly Box (less rugged but still effective)
– Cliff’s Bugger Beast (foam-based, good for larger flies)
– Fishpond Tacky Pilot (similar silicone design but with a magnetic closure)

Would you like help choosing the right size or comparing it to other fly boxes?