This is a slender and fine-looking Cartier TANK SOLO XL with model number 3800 . It comes with its box and book(s)/cert, and is in fantastic (virtually like new) condition!
This model features an automatic mechanical movement and a 'signature' Cartier matt-silver dial featuring stylized and bold-black Roman numerals, blue, sword shaped hands and a date indicator at the 6 o'clock position. The blued hands match the blue sapphire cabochon set into the winding crown
The strap to which the case is mounted is the original Cartier two-piece leather one, which is closed with a stainless steel folding clasp. The strap is in excellent condition, suggesting this watch is very unlikely to have been worn every day.