Features: DC5521 female to square port male charging converter adapter. Convert the 5.5x2.1mm interface power supply to square port power connector for charging laptop power adapters. Plug and play, convenient to use. Quality material, which ensures stability, durability and long service life. Small in size and light in weight, easy to carry. Specifications: Material: ABS+Electronics Color: black Female head: outer diameter 5.5mm, inner cylindrical diameter 2.1mm Male head: square port with pin Applicable models: for X1 Carbon YOGA 11S 13 and subsequent power adapters with square interfaces Package Includes: 1pc DC5521 Female to Square Port Male Adapter note: Please allow 1-2cm errors due to manual measurement. Please allow for slight color differences due to different display resolution.