What main features should I look for in a petrol hand held garden blower vac?

•  A powerful engine from 20cc up to 30cc or more producing air velocity of at least 200 KPH

 

•  Suction of at least 10m3 per second

 

•  Well-balanced and easy to use

 

•  Easy to start

 

•  A simple lever controlled function (blow/vac)

 

•  A shredding ratio of at least 10:1  

 

•  Shoulder straps for support and comfort

 

•  A detachable tube/s for easy storage 

 

•  Good power/weight ratio for easier working

 

•  A decent sized collecting bag