JBL ProSilent Aeras Micro Plus M

"Broad Airstone • New: made out of a extra fine pored silica sand mixture for outstanding fine air bubbles (therefore named “Micro”) • A new base plate allows a firm connection to the ground without being covered by gravel. • Size M: 14 cm long; Size L: 27 cm long • Can be linked with more aerating stones to form a row! • For fresh and salt water "