SlimStack board-to-board connectors have 0.40 mm pitch, 0.70 mm mated height and 2.60 mm width. Reportedly offer about 25% space savings compared to many competitive 0.40 mm pitch types. Features include two-point contact design and 0.18 mm wipe length; nickel-barrier plating; tactile click sound and feel, and gold-plated terminals. Are available in 20 - 50 circuits and have four solder tabs on each mating side. System is rated at 50V and 0.3A.
 
Molex Inc., www.molex.com/product/bb/slimstack04mm.html