Replacement parts for the Wolfgang Puck pressure cookers are difficult to find and I just received an e-mail back from an earlier inquiry to the the company advising that parts are available here:

http://www.wpcookware.com/categories.asp?cat=29

Not sure if your model is the BPCR0175 but if the part you require is not available on-line suggest you contact their Customer Service at 1-800-275-8273 or make an inquiry via their webform:

http://www.wpcookware.com/contact.asp