Sigma 17-50mm f2.8 EX DC OS for $400 (C/N; K-OS)

It’s Shiguma time! The Sigma 17-50mm f2.8 EX DC OS is on sale for $400 with $12 promotional rewards at B&H Photo in the Nikon mount and Canon mount. It also goes for $400 but without OS (optical stabilization) in the Pentax K-mount… The Canon and Pentax versions also go for $400 at Amazon…