From Sigma:
SIGMA WR PROTECTOR, SIGMA PROTECTOR, SIGMA WR UV FILTER and SIGMA WR CIRCULAR PL FILTER are scheduled to start the shipment towards the end of this month.
SIGMA WR* FILTER
SIGMA FILTER
*WR=Water Repellent
B&H has the Sigma WR Protector and Sigma Protector filters available for preorder.