Thickness of the screw threads about the hose needed to install with this head is less than 0.4inch.Please Check the dimention.
Connector(0.8inch or 2cm),Please check the image of the dimension about this product
The default working funtion is stream(the first funtion).
You can use the switch to transform stream to dispersed water(the second funtion).
The round button is only for making water pause and you should keep pressing this button to hold water off.Once you turn the water off or stop pressing the round button,it reverts back to the default working funtion(the first funtion).