Getue 20 ml Sterile Syringe with Luer Lock Tip - 50 Syringes by BH Supplies (No Needle) Individually Sealed

What gague is this luer lock? i need a blunt tip plastic tapered dispensing fill needle, and i need to know what size to buy.

how do I know what needle size to purchase for these? What a needle that is long but very thin, to be used to inject plants to kill vine boaring bugs.

Are these autoclavable?

can you draw liquid from opening of a bottle with syringe without the needle?