catflap.org Online Dictionary Query

  jar blocks /dʒˈɑː blˈɒks/
  Rammklötze 
     Synonyms: drop hammers, pile drivers, rams, tubs, drive blocks, drive hammers, driving sleeves, jar weights
  
   see: drop hammer, pile driver, ram, tub, drive block, drive hammer, driving sleeve, jar block, jar weight