Hi!
I think you're talking about the screwdriver that came in our old 54 Bit Driver Kit:
https://www.amazon.com/iFixit-54-Bit-Driver-Kit/dp/B008KOTNVA/ref=cm_cr_arp_d_product_top?ie=UTF8
Unfortunately we have discontinued producing and selling this kit on our website, replacing it with our much improved 64 Bit Driver Kit (the driver in this kit is larger but a major step up in quality):
[product|IF145-299]
Sadly, we no longer sell the kit or the screwdriver you're referencing directly. Still, a couple places (like Amazon) might have the 54 Bit Kit in stock for a little while longer.
Hope that helps!