Qseven is the smallest form factor with a size of 70x70mm² only. It's defined for low power and mobile applications.
congatec offers a complete range of COM Express Modules based on Type 2 pinout with basic (125x95mm²) and compact (95x95mm²) form factors.
congatec offers a wide range of COM Express Modules with Type 6 pinout on basic (125x95mm²) and compact (95x95mm²) form factors.
XTX is the expansion and continuation of the oldest established Computer-On-Module form factor ETX. It trades the no longer needed ISA bus with new features such as PCI Express and SATA.
ETX was the first successful Computer-On-Module concept ever. It was defined in 1998 as an open standard and is still supported.