Very impressed by the quality of the product, you are buying here directly from a manufacturer. They even kindly upgraded my shipping to Fedex without any additional fees, very great gesture. It's an heavy water-cooled spindle, 4.5Kg dry but not for cutting steel. Solid construction. It comes with two ER11 collet. The water will go through a stainless steel chamber so be careful of not using zinc, galvanised steel, aluminium, cadnium, cast iron, lead, mild steel, thin, lead-tin solder and chromium plate in your water cooling loop. I'm not sure if you can use G1/4 fittings with this spindle, it seems to be maybe compatible but the stock fittings already installed are very very tight, it will require a huge amount of force to unscrew them but it might worth to be tried. The stock fittings will be compatible with 5~6mm ID tube. Keep it up the great job <3