This battery shield is designed to fit the battery location on a HP-41 calculator and protects somewhat the calculator in the event the batteries leak. The shield can only be used with alkaline batteries, it can not be used together with the 82120A rechargeable battery.
The HP-41 family card reader (HP82104A) is a very useful accessory for storing and retrieving programs and data. The card reader presented here is in excellent condition, in original box with its manual. The device is recognized by the calculator as seen in the images. It comes with a number of used cards which will be very useful when testing it.
The HP-41 Blanknut version is a variant of the HP-41CV made by HP for customers who needed to sell the calculator bundled with their own software.