This unique t-shirt features Vacuum Tube schematics from a genuine vintage U.S. Patent filed in 1929! These shirts look awesome, fit well, are great conversation starters and an excellent gift for computer technicians, engineers and tech lovers! ★★★★★ PREMIUM T-SHIRTS We use high quality premium Gildan cotton t-shirts! These shirts are a cut above the rest. The ring-spun fabric is soft, smooth and comfortable with an athletic fit that provides excellent manueverability & a stylish modern look. You will look good and feel great in this shirt! ★★★★★ 5 STAR QUALITY & SERVICE We've been specializing in unique t-shirts and gifts since 2016, and we've built up an amazing collection (over 1,400 unqiue designs!). With over 12,000 happy customers on Ebay and counting, all you have to do is look through our feedback to see that these t-shirts are delighting people every day - and we'd love for you to join them! ► T-SHIRT DETAILS - Gildan Soft Style Short Sleeve T-Shirt - 100% ring-spun lightweight cotton - Crew neck collar - Athletic Fit ► T-SHIRT SIZING Small - Length: 28" (71cm), Width: 18" (46cm) Medium - Length: 29" (74cm), Width: 20" (51cm) Large - Length: 30" (76cm), Width: 22" (56cm) XL - Length: 31" (79cm), Width: 24" (61cm) 2XL - Length: 32" (79cm), Width: 26" (66cm) 3XL - Length: 33" (84cm), Width: 28" (71cm) ► SHIPPING & RETURNS - Free standard shipping nationwide! - Most orders ship in 2 to 3 days, in limited cases some orders may require up to 5 business days handling time. - Returns & exchanges accepted up to 30 days after delivery.