FOUR E'S SCIENTIFIC 10ml Pipette Tips, Disposable Universal Pipettor Tips Non-pyrogenic DNAse/RNAse Free Autoclavable Polypropylene(PP) -100pcs

This is a scientific product, not a consumer product. You likely knew that. The KEY feature is that this pipet is supposed to be LOW RETENTION -- meaning that no liquid stays inside. Most lab solutions have no problem completely leaving the pipet, but if you have a solution with a SURFACTANT (think soap bubble solution) then it's a different story entirely. For nearly all analyses that would require use of such a pipet as this EVERY TEENSY spec of a drop has to come out. Soap bubble / surfactant solution do not behave that way. THUS one must acquire "LOW RETENTION" pipets not to be fussing forever (never mind how) to get all liquid to come out of a normal pipet. EPPENDORF no longer manufactures LOW Retention pipets. At work I compared my solution (sodium hydroxide AND surfactant) as pipetted by 1ml normal pipet and 1ml low retention pipet (both eppendorf). HUGE difference. But we will set the score of 0, "ZERO percent magic" to that solution I stated as came out of a normal eppendorf 10-ml pipet. We will set the score to 100 "100% magic" to the 1ml eppendorf low-retention pipet. I NEEDED low-retention in a 10-ml pipet size. Allegedly THESE BE THEM (just not made by eppendorf). What WAS their score? ANSWER: 80% MAGIC. That's gosh darn good. Consider that you cannot even GET a low-retention 10-ml pipet from eppendorf. Consider that these pipets are SO INEXPENSIVE by comparison. They work with eppendorf pipetting instruments (that you plunger with your thumb etc.) But geometry is not the point. LOW RETENTION IS (otherwise, if you don't need that, buy any pipet tip). AND LOW COST is an excellent bonus. These are less than half the price of eppendorf.

I received the pipettor yesterday. I took it to work today to give it a try. It is relatively inexpensive, so my expectations were moderate. While it was a busy day, I did finally get a chance to try it out for a few minutes. To evaluate the device I used our lab's analytical balance. Reading out to 4 decimal places, it can resolve 10ths of a milligram. I arbitrarily chose to do 4 samples. I set the pipettor for 5ml and drew 5ml of type I DI water and check the mass of the draw using the balance. Obviously I was not doing a proper calibration check, I just had a few minutes to see what it would do right out of the box. The average of the 4 samples was 5.0128 grams. The lab was within 3 tenths of 20c all day long. Bottom line, the pipettor gave me a legit 5.0ml, all 4 draws. I am perfectly satisfied with what I saw today and look forward to putting the device through its paces in the future. So far? Absolutely worth the purchase. We'll see how it holds up to long term use.

Since I can wash and reuse these, this will probably last me a lifetime but I’m certainly not complaining about that! They work well and it’s nice to have extras on hand.

For my application these are reusable. If you need something truly use-once-and-throw-away then they might be a bit spendy. My only quibble is that there is no spare space at the top so if you are reverse pipetting it is all too easy for the liquid to get up inside the pipettor. The obvious solution would be to buy a tip that has a slightly larger capacity than you need but this seems to be the largest size available.

They work and they are a good price