Personalized Pocket Sealyham Terriers Long Sleeve T-Shirt. Sealyham Terrier dogs in a pocket illusion by Illustrator, Kim Niles of KiniArt studios. Pre-shrunk 100% cotton 6.1 ounce long sleeve t-shirt. Double-needle stitched neckline and sleeves. Quarter turned. Shoulder-to-shoulder taping. Adult: S, M, L, XL, 2XL, 3XL