Loc Blocs

Loc Blocs was a plastic block construction toy set.

[1] They were marketed in the 1970s and 1980s by Entex Industries and manufactured in Japan as Dia Block by Kawada Co. which still produces sets to this day.

They were also sold by Sears under their house brand Brix Blox.

Today, similar blocks are still manufactured in Japan as Diabloks and sold in the US under the name Disney Build-It.

The knobs were too tall and spaced just a little bit off for fitting between LEGO tubes.