What are the similarities between forward and reverse primers?

Forward and reverse primers have several points in common. 

Forward and reverse primers are both made from oligonucleotides. Both consist of 20 nucleotides and both possess short nucleotide sequences that’s complementary to the flanking ends of the DNA double strands. 

Forward and reverse primers are both synthesized commercially and designed for use in PCR reactions where both serve at starting points for DNA amplification. 

Both forward and reverse primers are essential components in PCR and both are annealed with the target DNA sequences. They are both temperature stable and generally have similar melting temperatures (Tm).