The large inner diameter of thin walled needles are designed to allow the use of a smaller gauge size with increased flow rates over regular walled needles.
Size 18 Monoject needles are the standard size regular walled needles for subcutaneous fluids. They are 1 inch in length and deliver 100 ml of fluids in 1 minute and 17 seconds.
Size 18 Thin Walled Terumo needles are the same size as the regular 18 gauge needles but deliver the fluids the fastest at 100 ml per 53 seconds. They are one inch in length.
Size 20 Ultra Thin Walled Terumo needles are commonly used, but unfortunately only the 1 1/2 in length is available, as the 1 inch length has been discontinued. Some people do find the length to be cumbersome. They deliver 100 ml of fluids in 1 minute and 59 seconds.
Size 21 Ultra Thin Walled Terumo needles are the smallest size ultra thin walled needles that we carry. They are one inch long and deliver 100 ml in 2 minutes and 38 seconds.