12 box of Madeira Aerolock Box filled with 12 x 1,200m Miniking Aerolock 125 overlock thread, 3 colours, black, white and grey. This set of threads includes: 3 Aerolock threads and 1 Aeroflock Woolly thread, in all 3 colours. 100% Polyester, the Aerolock bobbins hold 1200m of thread and the Aeroflock Woolly 1000m. The bobbins include a thread end lock which stops the thread from unravelling and keeps it secure. These aerolock threads are high quality for long-lasting seams and the aeroflock woolly threads are voluminous and perfect for elastic projects such as sportswear, dance costumes and leotards.