Great stuff Jon. The Reach catalog is in unbelievable conditon and full of great images, and I love the Spalding invoice. E.G. Koenig was a very big Sporting Goods retailer in the late 19thC and early 20thC in Newark. I have/had a glove, bat and uniform with their label.
I have taken a greater interest in 19thC paper and advertisig lately, but only started the hunt. (and Mike's 19thC postal covers thread has me jonesing for more). Picked up this Spalding card a couple weeks ago on ebay for a few bucks. (back and front scans below). Not terribly full of content like your invoice, but couldn't pass it up for price.
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