Go to this site for sizes, but here is an explanation:

Our Pyrex brand and Borofloat sight glasses are made from borosilicate glass. We also offer Vycor brand sight glasses which are made of number 7900 96% silica glass. Both are widely used in industry and are well known for their mechanical, chemical and thermal stability. A noteworthy difference between our Pyrex and Vycor brand sight glasses is that Pyrex can be heat treated or tempered to about 3 times its annealed strength, but Vycor cannot be tempered due to its extreme heating temperature.

* http://www.kaufmanglass.com/safety.htm

Compliance voltage is the voltage available at the counter electrode that can be used to force current to flow and still maintain control of the working electrode voltage. The compliance should be specified in conjunction with a current value: "20V @ 200mA" or "20V @ full rated current". An amplifier's output voltage decreases at higher currents due to the output impedance of the amplifier.

The voltage at the counter electrode is needed to force the electrochemical reaction at the counter electrode to proceed and to overcome the iR drop through the bulk of the electrolyte solution. Compliance voltage can become important when the currents are high, or when the conductivity of the solution is low (dilute electrolytes), or when a high resistance sintered glass or Vycor frit has been used to isolate the counter electrode.

In practice, depending on the electrolyte and cell design, the potentiostats useable limits may be defined by either its maximum current specification or its compliance voltage limit. In either case, if the limits are exceeded the potentiostat will be unable to properly control the voltage of the working electrode.

Example for testing compliance voltage

Construct a "dummy cell" with the following resistors, and connect the leads of the potentiostat as shown:

This is representative of a cell with electrolyte of low conductivity. As the reference electrode is generally placed closer to the working/sense (the junction across which voltage is controlled and/or measured depending on potentiostatic or galvanostatic control, respectively), there is less impedance than between the counter and working/sense.

Request the potentiostat to apply a 5V potential (i.e., a Chronoamperometry experiment), and you will see a current of 5mA current (as expected).

USP Type I borosilicate glass is the least reactive glass available for containers. It can be used for all applications and is most commonly used to package water for injection, UN-buffered products, chemicals, sensitive lab samples, and samples requiring sterilization. All lab glass apparatus is generally Type I borosilicate glass. Examples of Type I borosilicate glass include Corning® Pyrex® 7740 and Wheaton 180, 200, and 400. Though Corning® Vycor® 7913 is not classified as a Type I glass, it does meet or exceed USP Type I requirements.

In most cases Type I glass is used to package products which are alkaline or will become alkaline prior to their expiration date. Care must be taken in selecting containers for applications where the pH is very low or very high, as even Type I glass can be subject to attack under certain conditions. Although Type I borosilicate has the least pH shift of any glass, there still may be some sensitivity with certain packaged products.

Surface treatment is not usually required, however it will further enhance the desirable characteristics of an already superior container. This surface enhancement may become especially important for small containers because of the high ratio of container surface area to the volume of the container contents.

USP Type II de-alkalized soda-lime glass has higher levels of sodium hydroxide and calcium oxide. It is less resistant to leaching than Type I but more resistant than Type III. It can be used for products that remain below pH 7 for their shelf life.

USP Type III soda-lime glass is acceptable in packaging some dry powders which are subsequently dissolved to make solutions or buffers. It is also suitable for packaging liquid formulations that prove to be insensitive to alkali. Type III glass should not be used for products that are to be autoclaved, but can be used in dry heat sterilization. Examples of Type III soda lime glass include Wheaton 800 and 900.

USP Type NP soda-lime glass is a general purpose glass and is used for non-parenteral applications where chemical durability and heat shock are not factors. These containers are frequently used for capsules, tablets and topical products. Examples of Type NP glass include Wheaton 810 and 910.