Metal or Wire Buckles are used with plastic strapping to join the straps. Metal Seals are designed to be used with a sealer or crimper that crimps the seal onto the strap forming the join in the strap to hold it together. Buckles are able to be used without the need for tools, although a tensioner can be used to tension the strap. 
 
Available sizes 
13mm, 16mm, 19mm, 32mm