 A 6U VPX board features six 16-column 7-row RT2 connectors and one 8-column 7-row RT2 connector, while a 3U board features two 16-column 7-row RT2 connectors and one 8-column 7-row RT2 connector.Also new for VPX boards are alignment/keying blocks which are designed to be sufficiently robust to prevent pin stubbing.The blocks also provide card keying and a safety ground.