There are three TT-4A machines for sale on eBay. www.ebay.com/itm/Vintage-TELETYPE-WRITER-Machine-lot-parts-repair-US-Army-Signal-Corps-/280800719313 $550 for the lot. Two look like they're in good condition - no visible rust and a roll of paper still in place. One appears to have a tab stop option. John Nagle