This Westbrass 1-3/8" zinc bath tub stopper in Polished Chrome is used with fine-thread tub shoes to seal the bottom of the tub. The stopper is sealed to the bottom of the tub with silicone caulking or plumber's putty. The stopper can be sealed with a rubber stopper a tip-toe a twist-and-close or push/pull mechanism that utilizes a flat rubber washer seal. Mechanism or seal sold separately. Color/Finish: Polished Chrome. Zinc construction. Polished chrome finish blends into your existing fixtures. Fine-thread body. 1-3/8" NPSM (1-5/8" by 16 UNC) exterior. Use with a fine-thread shoe and a tip-toe twist-and-close lift-and-turn or push/pull mechanism that utilizes a flat rubber washer seal (mechanism and seal sold separately) . Fits 3/8" mechanism stems (sold separately) . Assembled Depth: 2.5". Assembled Height: 2.5". Assembled Width: 2.5". Material: Zinc. Plumbing Part Type: Bath Drain/Drain Assembly. Strainer Included: No.