Philippines

hollow blocks molds hard plastic re usable 500times 400x100x200mm size
Pour fresh concrete on the mold then dry if for 48 hrs, then demould using your hand.  Mix 1:3 ratio.  Ladies you can do it too!!!!
Other supplier does not offer you this type of suggestions on how to do it!
Note:  If in case the mold will stick to the cured concrete during demolding after 24-48hrs, spray or paint brush (1 inch) the "in sides" and bottom of the mold with liquid release agent (available also online here which is more cheaper than cooking oil) during block making. that is before pouring the fresh concrete to the mold so that no difficulty in demoulding using your hand.
Features: 
Save Power, Save Labor, Higher Quality and Capacity. 

1. The interlocking plastic paver concrete hollow blocks no need
machine to produce the concrete blocks for your house
2. The final block from this mold is with smooth surface no finishing needed.
3. Most importantly, this block can be 100% interlock
more efficient to save time to build a house.