What is LTR and RTL?
The main difference between left-to-right (LTR) and right-to-left (RTL) language scripts is the direction in which content is displayed: LTR languages display content from left to right. RTL languages display content from right to left.
Is slider good UX?
Sliders are excellent UI controls, but they are not one-fits-all tool. They are good when users want something that is relative, but not very good for exact values. When designing a slider, measure interaction cost and make sure that the users can select that range (or single value) correctly from the first attempt.