R135 - Screen Wash

Highly concentrated cleaner
Use in both summer and winter
Helps to prevent re-freezing of windscreen during cold weather
Very effective at removing road film and grime from your windscreen
Clears insects and dirt
Helps to keep sprayer jets clean and clear of blockages
R135 will leave no visible residue upon your screen
R135 can be used at a number of concentrations from neat in the coldest winter months when it will give protection down to -20oC to 10% (1 part R135 : 9 parts water) in the warmer summer months.

Can you explain the dilution rates?

Neat is just that, you don't dilute the product at all. 20% dilution means that you would add 2 litres of product to 8 litres of water and 10% would be 1 litre of R135 to 9 litres of water.