... 2,High quanlity; 3,Iron core, steel core, PE core, PE core is better The core material can be iron, steel and PE,PE ... the best.In this picture, the core is made of iron.It is not good enough.In this ... PE core is better than steel core.This core is the best.In this picture,the steel core,the iron core and ... the PE core is put together. marine push pull ...