B inner unit used with B cone,plastic cone, to fix formwork in building construction also have D inner unit used with ... and building fastener such as form tie,plastic cone,B-cone,D-cone,inner unit, D-form tie ... ,pin,wedge,wedge pin,form tie,B-cone,D-cone,hex nut,flat tie ,wall ... and other non-standard fastener most of them are used in building ,channel,bridge construction to fix formworks skype ...