Our basic student organic chemistry molecular model set, the 68845NV aka "Foundation" is highly versatile. It provides bond length accuracy not found in many more expensive sets. It comes with 20mm bonds for use with hydrogen atoms, such as C-H, O-H, S-H. The 30mm bonds are used with larger atoms, e.g. C-C, C-O, C-S.
15 35mm bonds are included for larger atomic radius elements such as P (phosphorus). The 6 50mm flexible white bonds can depict double bonds such as C=C or C=O or triple bonded C≡C.
Every Orbit molecular model set sold by Indigo Instruments is fully compatible with others you might own. You can replenish any set or customize it with Genuine Cochranes of Oxford Orbit Atoms.
I've had consistently great service from this company. Our students seem to really appreciate the reasonable price. In the years that we've used this product, not one has been returned due to defects.
Considering how many of these we sell to schools every year, that is high praise indeed. Thanks letting us know.