50/50 vape juice is most suitable for pen-style cigarette mimicking devices and tighter draw devices that run at lower wattages (often referred to as MTL or Mouth to Lung), giving you an incredibly balanced mix of flavour and throat hit. 50pg 50vg which makes the liquid ideal for starter pens, higher nicotine, pods and Mouth To Lung devices. If used in a Direct to lung device there is a chance of some leaking.
E-Liquids can come in a variety of ratios 50pg/50vg and High Vg 30pg/70vg are a couple of the most popular but what does it mean?
In simple terms the PG figure shows how thin a liquid is and the VG shows how thick.
Certain devices work better with certain ratios also different people have a preferred ratio It is often the case that the VG is smoother than PG.
In the main a Sub Ohm kit or Direct to Lung or more cloudy device would require a higher VG content and a Mouth to Lung would require a more balanced ratio like a 50pg/50vg This is where the term E-Liquid Ratio comes from.
Go to link to learn more about What is Direct to lung and Mouth to lung