Our HERM SPRENGER Dog Chain Training Collar is a safe effective training tool with proper use. Sophisticated production techniques consistent quality control superb craftsmanship and the highest quality raw materials make HERM SPRENGER German chain products superior. Available in a variety of sizes: 2.0 mm x 14" 2.0 mm x 16" 2.0 mm x 18" 2.0 mm x 20" and 2.0 mm x 22"; 2.5 mm x 16" 2.5 mm x 18" 2.5 mm x 20" 2.5 mm x 22" and 2.5 mm x 24"; 3.0 mm x 18" 3.0 mm x 20" 3.0 mm x 22" 3.0 mm x 24" and 3.0 mm x 26"; and 4.0 mm x 22" 4.0 mm x 24" 4.0 mm x 26" and 4.0 mm x 28". HERM SPRENGER offers a variety of high-quality specialty chain products.